tests: Windows compatibility fixes
- printenv.py, md5sum.py, simplemerge, test-archive, test-merge1,
test-merge-symlinks: set standard streams to binary mode
- test-encode: replace "gunzip" by "gzip -d"
- test-hup: requires fifo
updating working directory
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
pulling from ../a
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
(run 'hg update' to get a working copy)
1 files updated, 0 files merged, 1 files removed, 0 files unresolved