a new approach to shortening filenames / paths
setting renamed / repurposed
Merge remote-tracking branch 'upstream/master'
account for empty / non-absolute target directory; bugfix
new renaming setting
build_ui against options_renaming
tests and subsequent fixes
Merge remote-tracking branch 'upstream/master'

Conflicts:
	picard/file.py
	picard/ui/options/renaming.py
small oops
readability improvements
path shortening that takes into account different encodings
small fixes and some comments
Merge remote-tracking branch 'upstream/master'

Conflicts:
	picard/file.py
small calculation fix
Merge remote-tracking branch 'upstream/master'
Characters counted in UTF-16 code points where appropriate.
NFD handled under OS X.
Windows bugfix when the relative directory path is short enough.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'

Conflicts:
	picard/util/__init__.py
	test/test_utils.py
moved filenaming stuff to its own module
Messing with settings:
Revert `options_renaming` UI files back to upstream/master (gets rid of `move_files_ancestor`).
Stick to `windows_compatibility` setting name, and handle upgrade.
Rename `move_files_ancestor` setting to `windows_compatibility_drive_root`.