Better handling of issues during python setup

Fixes #1151
Updating to latest ycmd
Updating docs with correct defaults for option

Fixes #1156
Updating vimdoc from README
Append to no_proxy instead of overwrite

Overwriting no_proxy may cause some trouble for other plugins using network in environments with proxy exceptions, e.g. vim-fugitive
Merge pull request #1163 from m42e/master

Append to no_proxy instead of overwrite
Fix KeyError on no 'no_proxy' env var
Docs now more specific how glob matching works.

Fixes #1166
Add functionality for disabling and enabling Ycm autocompletion.
Change function names and make them public.
Remove commands for lock and unlock.
Moved some code around
Updated to latest ycmd
Fix handling of signs placed by other plugins

It appears to address numerous amount of issues, including: #812, #801, #887.

Proposed solution uses dummy sign which is placed before updating
diagnostic signs and unplaced afterwards, which eliminates any
flickering. Also, it not just unplace all, it unplaces only that marks
that are changed, so performance should not be an issue in case of many
diagnostic messages.

It's common solution that can be found in some vim plugins that manage
signatures.

Signed-off-by: Stanislav Seletskiy <s.seletskiy@gmail.com>
Minor refactoring & stylistic changes.
Merge branch 'seletskiy-master2'
`set -e` in install.sh

This allows error in `build.sh` to propagate up. Fixes #1197.
Merge pull request #1201 from oconnor663/master

`set -e` in install.sh
Now using a libclang based on Clang 3.5.

This is now the officialy supported version of libclang for YCM. The
changes come as a result of updating to the latest ycmd commit.
Updating to latest ycmd.