- api cleanup and unit tests added for 2d geometry
 * correct parsing of radius and diameter
 * merged rectangle and rounded rectangle into rectangle
 * added auto extrude to CSGBase "add" method if child being added is a 2d shape
 * experimenting with corner rounding locations
 * lots of unit tests added
- more work done on geometry and testing
 * merged cylinder with rounded cylinder, added correct params parsing for that too
 * brainstormed, implemented and partially tested a bit based system for setting "locations" see parseOptionAsLocations in csg/utils:
using bitwise operations, various locations 'top left', 'bottom front' etc can be set : for now only the bitmask part is done, now to use it
- finally got settable corners working for rectangles (2d)
 * not the cleanest but not too bad for a first attempt, works using bit level flags and bitmasking
 * still buggy for "right" locations (as in, on the right)
 * the location parser might need to be changed a bit/ need to review the various bitflags

- other cleanup and fixes
 * fixed centering issue with circles (2d)
 * added normalize and setLength method to vector2d : these are also a slight movement towards the THREE.js api as far as vectors etc go
 *small fixes here and there