Fixed conversion between big endian and little endian.
For speedup sort strings in 8 times for string length: 1/2/4/8 bytes.
By using optimized radix sort for GPU.
Fixed a bug in groupby op. Added support for storing results as binary files.
Speedup of sort strings in 2 - 3.5 times.
For strings length is a multiple of two speedup in 2 - 2.5 times, for multiple of four in 3 - 3.5 times. (Speedup through accelerate of comparison of static strings.)
Merge branch 'master' of github.com:antonmks/Alenka into optimize_sort_strings
Merge pull request #32 from AlexeyAB/optimize_sort_strings

Optimize sort strings (speedup in 2 - 8 times).
Merge pull request #7 from antonmks/master

update source code