Add --write-cache argument that enables updating outdated cache
Filter out __MACOSX directory

This directory [contains some metadata for finder][1] meaning that it should not 
be taken into account when determining significant files.

[1] http://old.floatingsun.net/2007/02/07/whats-with-__macosx-in-zip-files/index.html
Make autoget.py create data for vim-ctrlspace
Make more plugins autoget.py responsibility
Fix args check
Use only set() and io.BytesIO()
When using CodeGoogleMatch also obtain files from cache for subversion
Make one more source autoget.py responsibility