added lowest_eig_potential.h, missing orthogonalization
added orthogonalize class
implemented OrthogonalizeTranslation and cpp tests
added lowest_eig_potential tests
make gradient optimizer get functions constant (to guarantee that the arrays are not modified)
fixes
fix
implemented distance virtual interface
reorganised modified_fire with .cpp and .pxd files
Merge pull request #44 from smcantab/new_fire

Re-implemented FIRE, added orthogonalization classes and numerical method to compute lowest eigenvalue, added interface to distance to pass a pointer to the distance class without templating the user class
bug fix to tolerance in modified_fire
add missing include
Merge branch 'master' into new_array
remove reisize() from some recently added tests