A base expression visitor class for dynamically-typed languages.

This is potentially useful for Python, PHP, JS and Ruby.
For documentation on what it does, see the docs in the header file.
It's not a lot of shared functionality, but it is a piece of shared /
suggested architecture which makes it a) easier to write new language
plugins because there is a clear path for solving this problem; and b)
easier to understand other language plugin's architecture, because they
all work similar.
SVN_SILENT made messages (.desktop file)
allow resizing stuff in the history dialog by layouting it with spitters
Ask user for confirmation before git checkout -- <path>

Since this discards all local changes irreversibly, it's too easy
to fat-finger in that clumsy menu and needs a confirmation.
Use libkomparediff2 from kdesdk

Remove our own copy

REVIEW: 115017
Merge remote-tracking branch 'origin/master' into frameworks