* Adding methods for returning Gene and Transcript objects
* unified locus/loci methods (e.g. gene_names_at_locus(c, i, i+10)
* improved GTF parsing by supporting biotypes of old releases, realized gene names can have multiple locations
* change asserts to exceptions, made Locus base class for Gene and Transcript
* added more documentation on GTF columns and reconstruction logic
Merged pull request #3: Combined locus/loci, info objects for genes & transcripts, reconstruct missing entries & columns for old releases
version bump