Move orc directory inside kernels/volk

Rationalize top-level directory structure
Fix typo from last commit

Orc kernels were moved into kernels/volk/asm/orc
Code style fixups: PEP-8 compliance

Remove unneccesary semicolons, unused imports, other minor style issues
Merge branch 'directory_restructure'
adding float, int32, and int16 FFT kernels
Merge branch 'master' of github.com:n-west/volk
Merge branch 'fft'
Merge branch 'fft'
Merge remote-tracking branch 'upstream/master'