first Cython file
comparing two Coord3D
add method for Coord3D
use the cpp version of operator== instead of a cython defined one
revert to the Coord3D name instead of PyCoord3D
use C++ implementation of Coord3D add operator
added scalar multiplication (although only vector*scalar) and __str__ methods
norm2 method
instantiate rigidbody
playing with cython return types + __len__ method added for rigidbody
some work on rigidbody interfacing
ptools.pyx split into two files: rigidbody.pyx and coord3d.pyx
fixed strange chars in error message
added getCoords method to rigidbody
Added contructor: Rigidbody(Rigidbody).

TODO: find a name more appropriate than 'filename'
removed debug messages
added Rmsd calculation
added FindCenter(). Fixed unittest.py to reflect new Python inteface
fixed mul method, updated tests for Norm --> norm

in Cython __mul__ behavior differs from regular Python __mul__ method and is called instead of __rmul__
Coord3D copy constructor