Improved resource unloading. Make it possible to unload all resource types by partial name at once. Editor unloads unnecessary resources after scene load or clear. Add weak ref check to all resource unloading to avoid shader programs being left without their parent shader.
Add int versions of Max, Min & Clamp to the AngelScript API.
Force elements in layout to left/top alignment, warn if has different alignment. Closes #34. Implement editor accelerator key texts a bit differently as the right alignment in a layout -hack can no longer be relied upon.
Fix NinjaSnowWar compile error.
Fix wrong build path in cmake_android.bat for detecting cache value.

Also enhance to suppress symlink creation warnings when they are already created and update Android toolchain for NDK r9b.
Merge remote-tracking branch 'upstream/master'