Updated formats.bed.gff() to better handle missing fields in bed file.
Added `--log` parameter to assembly.preprocess.trim(). Added
`--add_attrib` parameter which takes a two-column tab delimiter file
containing ID to look for in GFF file and attribute value to add
(attribute name will be the name of the file)
Merge branch 'master' of github.com:tanghaibao/jcvi