removed extraneous whitespace
BCSWavefunction.hpp should not assume amplitude_t is the same as complex_t
always include vmc-typedefs before eigen

this is in case we want to use a numeric type that needs to be
included (defining traits for itself) before eigen is included
make VMC_AMPLITUDE_T configurable
BoundaryCondition.hpp now works for a real phase_t
complex_pow() now works with more general types