minirst: fix container stripping logic

share: allow trailing newline on .hg/sharedpath. This is extremely handy for those occasional circumstances where you need to edit .hg/sharedpath manually, since modern Unix text editors make it surprisingly difficult to create a text file with no trailing newline.

contrib: some support for named branches in zsh_completion (issue2988) named branches were not included for autocompletion in zsh. by adding _hg_branches and calling it from _hg_labels, named branches are now included when autocompleting many commands in zsh. support for completion of hg log -b was also added. there are possibly other cases where support needs to be explicitly added.

test: test for options duplicate with global options issue2995 should not happen anymore

merge with stable

rollback: improve readability; clarify that the return value is an int.

demandimport: determine at load time if __import__ has level argument

win32: quietly ignore missing CreateHardLinkA for Wine

osutil: avoid accidentally destroying the True object in isgui (issue2937) Needed to use 'Py_RETURN_TRUE' instead of 'return Py_True' to avoid reference count errors which would randomly crash the Python executable during merge. This only happened when you had something configured in merge-tools and the merge was large enough.

merge with stable