NTP style universe clock synchronisation.

Dynamic warp idea thanks to dazoe.
Avoid future window id conflicts.

I preserved the old window ids as hint, so we can have 2 windows with
same id if needed, hints can be removed if there are no plans to use
them.
Improved server-side mod control, added options for non-SHA checked required and optional files. Fixed some bugs with the client SHA hashing of loaded files.
Git attributes so we don't fight with line endings.
Implemented multithreading for SHA checking on load, with load time reduced to ~30% of previous
Added display for debugging purposes
Merge pull request #624 from kkotowick/server-side-modcontrol-upgrade

Further improved server-side mod control
Merge pull request #615 from hashashin/master

Avoid future window id conflicts
Merge pull request #597 from godarklight/ntp-sync

NTP style universe clock synchronisation.
Merge pull request #623 from godarklight/git-attributes

Git attributes so we don't fight with line endings.
Normalize line endings.
Merge pull request #640 from godarklight/normalize-line-endings

Normalize line endings.
Fix a connection dropout when trying to send a null message. Also rename the error message in asyncUDPSend.
Merge pull request #641 from godarklight/send-error-fix

Fix a connection dropout when trying to send a null message.
Fix #647
Merge pull request #648 from godarklight/fix-647

Fix #647