OpenSCAD train track library SE

Based on srepmub's OpenSCAD train track library, with a few additions. I can now make pretty much any track layout I can imagine! This is pretty much why I bought a 3D printer. :-)

Changes:
1) Improved SCAD file readability (renamed methods & variables)
2) Added some new tracks (triple track, double curve)
3) Added smaller radius turns (curved and straight track small)
4) Works with connector thing http://www.thingiverse.com/thing:15165