Use xbob.blitz instead of blitz.array; Simplify bindings

.gitmodules

buildout.cfg

setup.py

src/blitz.array

src/xbob.blitz

xbob/core/convert.cpp

xbob/core/random/binomial.cpp

xbob/core/random/gamma.cpp

xbob/core/random/lognormal.cpp

xbob/core/random/main.cpp

xbob/core/random/normal.cpp

xbob/core/random/uniform.cpp