MP2E's compiler doesn't have an overload of abs() for long long; use llabs instead.

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2820 86ba831e-150c-0410-ab35-e06eaae15ed9
* Add Odamex to "significant code" section w/special credit to dr_sean
* Alphabetize significant code and libraries/utilities lists

git-svn-id: http://mancubus.net/svn/hosted/eternity/trunk@2821 86ba831e-150c-0410-ab35-e06eaae15ed9