Change gitignore

Copied from https://github.com/github/gitignore
Merge pull request #658 from mkalb/gitignore

Change gitignore
Replaces existing skysphere and tweaks some parameters accordingly.
Update credits + minor related tweaks
Added the license the the NearestSortingList
- New getter in LocalPlayer now also returns the IO var given as parameter.
- Removed example from EntityRef
- Removed wring spelling correction from CoreReg
- Major restructure of the code in NearestSortingList for better readability. Part of this is adding the distance comparator.
- NearestSortingList is now generic to the origin entity, around which the other contents are sorted.
removed unused dependancies.
Updating to the latest dev version for easier merge with the dev branch.