add support for blastx
add more blast options
add more tests
add helper to get back feature object from blast result
use as_dna and as_feature methods in tests
remove truncated matches across boundary
fix choices definition for dna_or_protein field
updated README from master
merged master into blastx
Merge branch 'blastx' of github.com:benjiec/giraffe into blastx
merged changes from aster
Merge branch 'master' into blastx
Merge branch 'master' into blastx