Merge pull request #29 from daisieh/p17

Fixes #17.
Merge pull request #30 from daisieh/p23

Fixes #23
Merge pull request #31 from daisieh/velvet

Added -velvet flag (mostly for debugging): it redoes velvet assemblies
on blast results generated from previous sTRAM runs.
Oops, evalue needs to be a float, not an int.
Merge branch 'juliema'