Docs now state Ubuntu 14.04 has good Vim version.

Fixes #1205
Unlike the other functions, youcompleteme#EnableCursorMovedAutocommands and youcompleteme#DisableCursorMovedAutocommands are not overwriting. This causes an error if the file is reloaded.
Minor refactoring
Fix Vim E885: not possible to change sign

Clang will sometimes give a diagnostic for line 0, and Vim borks on
placing signs for line 0.
update ycmd dependency