added fast path for Ddot
added fast path for Dasum
improved fast path for ddot
fast path for Dswap
fixed bug in dswap fast path
improved code in ddot fast path
improved code in ddot fast path
added fast path for incX
added fast path for Dcopy
fast path for Daxpy
fast path for Drot
added caching for slow path in Drot
fast path for Drotm
improved caching for Drotm
fast path for Dscal
Added test cases for fast path when n != len(x)
Fixed missing return in Drotm fast path
Fixed missing return in Dcopy