tests/test-push-r.t

i18n: calculate terminal columns by width information of each characters

neither number of 'bytes' in any encoding nor 'characters' is
appropriate to calculate terminal columns for specified string.

this patch modifies MBTextWrapper for:

  - overriding '_wrap_chunks()' to make it use not built-in 'len()'
    but 'encoding.colwidth()' for columns of string

  - fixing '_cutdown()' to make it use 'encoding.colwidth()' instead
    of local, similar but incorrect implementation

this patch also modifies 'encoding.py':

  - dividing 'colwith()' into 2 pieces: one for calculation columns of
    specified UNICODE string, and another for rest part of original
    one. the former is used from MBTextWrapper in 'util.py'.

  - preventing 'colwidth()' from evaluating HGENCODINGAMBIGUOUS
    configuration per each invocation: 'unicodedata.east_asian_width'
    checking is kept intact for reducing startup cost.

  $ hg init test
  $ cd test
  $ hg unbundle $TESTDIR/bundles/remote.hg
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 7 changes to 4 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg up tip
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ..

  $ for i in 0 1 2 3 4 5 6 7 8; do
  >    echo
  >    mkdir test-"$i"
  >    hg --cwd test-"$i" init
  >    hg -R test push -r "$i" test-"$i"
  >    cd test-"$i"
  >    hg verify
  >    cd ..
  > done
  
  pushing to test-0
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions
  
  pushing to test-1
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 2 changesets, 2 total revisions
  
  pushing to test-2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions
  
  pushing to test-3
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 1 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 4 changesets, 4 total revisions
  
  pushing to test-4
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 2 changesets, 2 total revisions
  
  pushing to test-5
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions
  
  pushing to test-6
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 5 changes to 2 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 4 changesets, 5 total revisions
  
  pushing to test-7
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 6 changes to 3 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 5 changesets, 6 total revisions
  
  pushing to test-8
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 2 files
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 5 changesets, 5 total revisions

  $ cd test-8

  $ hg pull ../test-7
  pulling from ../test-7
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 2 changes to 3 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 9 changesets, 7 total revisions