Merge branch 'three-particle-binding' of git://github.com/gizeminci/espresso into three-particle-binding

Conflicts:
	src/python/particle_data.pyx
	src/python/utils.pyx
Merge branch 'master' of git://github.com/gizeminci/espresso into three-particle-binding
python: Work on bonds
Merge branch 'three-particle-binding' of git://github.com/gizeminci/espresso into three-particle-binding

Conflicts:
	src/python/particle_data.pxd
	src/python/particle_data.pyx
	src/python/utils.pyx
Collision detection three particle binding
Merge remote-tracking branch 'rudolf_github/three-particle-binding' into three-particle-binding