Fixed X11 synchronization when message queue is

enabled and synchronize access to the 'waiting_for_input' variable
Remove unused variable
Fix 'has' function to report 'messagequeue'
Add documentation
Add messagequeue conditional to snake.vim
Add --with-features=huge to the instructions
Use 'char_avail' to check for input in background
Fix some deadlocking problems in message_queue.c
Refactor message_queue module.

Now it contains the actual message loop. Consumers just need to call the
'message_loop' function to wait for user actions.
Add ycm_extra_conf
Simplify ycm_extra_conf
Restored to master
Add lvimrc
Refactor a lot
Fix previous
Simplified IO semaphore
Rename feature to 'event_loop'
Fix previous
Fix 'timedwait' function
Disable poll loop when a timeout is specified