Add cl_vector_length trait.
Random generator (uniform and normal distribution).
Philox algorithm from Random123.
Merge branch 'master' of https://github.com/ddemidov/vexcl
Merge remote-tracking branch 'neapel/master'
documentation fixes
Fixed OpenMP check in CMakeLists.txt
Got rid of unused variables warnings
Fixed ViennaCL examples
Referenced arch pkgbuild in INSTALL

Thanks, @raedwulf!
Split index and seed into two arguments.
Merge remote-tracking branch 'neapel/master'

Conflicts:
	vexcl/random.hpp