Commit to add "Coverage" option to procedural terrain generator

This commit adds a "Coverage" option to the procedural terrain
generator. Allows mixing of textures. See
http://www.garagegames.com/community/blogs/view/22371 for more info.
This version has many improvements - coverage is now entered as a
percentage, accepts decimals, and doesn't have any bugs as far as I
know.
Increased stability Torqu3D: unit-tests running without a crash. See the console.log after ran unitTest_runTests( "", true ). @signmotion
Don't assign NULL to a Vector.
Move CMake library's files to libraries dir.
Clean CMake files.
CMake changes for dedicated builds.
Fix for error on Clang compiler: reinterpret_cast from 'const void *' to 'FunctionType *' (aka 'void (*)(EngineObject *, const char *, const char *)') casts away qualifiers
         return R( reinterpret_cast< FunctionType const* >( /*const_cast<void*>*/(mFn) )( mThis, a, b ) );
Fix error on Clang compiler: 'ival' is a protected member of 'Dictionary::Entry'
Merge remote-tracking branch 'JackDavidson/master' into procedural-terrain-coverage
Fix random number generation.
Merge pull request #687 from eightyeight/procedural-terrain-coverage

Add coverage option to procedural terrain generator
Merge pull request #681 from BeamNG/fix_cmake_linux_dedicated

Fix CMake linux dedicated on gcc and Clang
Merge pull request #674 from eightyeight/fix-tsignal-mtriggernext

Fix SignalBase constructor shenanigans
Merge remote-tracking branch 'LuisAntonRebollo/unit-tests-without-crash' into development