g:ycm_semantic_triggers now only adds new triggers

Fixes #164.
FAQ item for UltiSnips key conflict

Related to #381
Option to set min length for suggestions

Only works with the identifier completer. Fixes #387.
Don't call SyntasticCheck if not syntastic checker

If the user forced YCM to not register itself as the Syntastic checker, we
should not be calling SyntasticCheck since that would slow down everything.

Fixes #416
Minor formatting changes to docs
Encouraging the user to read the docs even more

Apparently we weren't encouraging enough before. Related to issue #415.
fix jedi DeprecationWarning
Add version check for Vim 7.4
Merge pull request #427 from viszu/master

Make it work with Vim 7.4
Adding OnVimLeave support to Completer class
Merge pull request #424 from beards/master

fix jedi DeprecationWarning
Typo fix in docs
Fix duplicate entries in filename completion

We could just remove the "dup: 1" part in the completion dict, but that would
leave the duplicate removal up to Vim which would be slow. Also, we might not
end up returning the correct number of results then.
Code style fixes
port ycm to python3