Bug fix: Encode ":" on Mac OS X in xolox#misc#path#encode()

Reported here: https://github.com/xolox/vim-notes/pull/28
Improve xolox#misc#buffer#prepare()
Merge branch 'master' of https://github.com/xolox/vim-misc
Remove misc/notes/user/README, add .gitignore, document g:notes_directory (issue #28)
Fix a stupid bug in search-notes.py (and clean it up a little)