cmdutil: use '[committemplate]' section like as map file for style definition
Before this patch, each template definitions for 'changeset*' in
'[committemplate]' section have to be written fully from scratch,
even though many parts of them may be common.
This patch uses '[committemplate]' section like as the map file for
the style definition. All items other than 'changeset' can be referred
from others.
This can reduce total cost of template customization in
'[committemplate]' section.
When the commit template other than '[committemplate] changeset'
is chosen by 'editform', putting '[committemplate] changeset'
value into the cache of the templater causes unexpected result,
because the templater stores the specified (= chosen) template
definition into own cache as 'changeset' at construction time.
This is the reason why '[committemplate] changeset' can't be referred
from others.
Issue351: mq: qrefresh can create extra revlog entry
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ hg qinit
$ echo b > b
$ hg ci -A -m foo
adding b
$ echo cc > b
$ hg qnew -f foo.diff
$ echo b > b
$ hg qrefresh
$ hg debugindex b
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 3 ..... 0 1e88685f5dde 000000000000 000000000000 (re)