hgk: display branch name in diff header

Display debugstate dates as '%Y-%m-%d %H:%M:%S'

merge: add a bit more sanity to divergent copy checks

keyword: test that expansion is done filewise Checks issue fixed in 2a66138c5e7e.

Solaris compatibility fixes for test-keyword: - do not use /bin/false (yields 255 instead of 1) - do not use "cd -", simply use "cd .." instead.

convert: separate trunk detection from branch layout detection In some subversion repositories, trunk is present but no branches are used. The current code is assuming that both trunk and branches must exist before adding trunk's head to the heads list. It's just better to separate the branch layout stuff from the trunk one.