Extension

The purpose of this pull request is to:-
1. Convert the vecmath library to a jruby-extension (pre-compiled)
    Greatly simplifies use of ArcBall, and Vec2D and Vec3D can be written directly as vertex etc. 
2. Add a DegLut facility for sin and cos (also a jruby-extension)
3. Change jruby-install to a sub-menu of rp5 (from a separate executable)
4. Upgrade to jruby-1.7.13