Pyvariant

Features:
- add variant mapping
- add logic for fetching sequences
- add additional functions for getting feature information

Features:
- add contig to * mapping functions
- add 'get_info' functions for gene, exon, and protein

Bugfixes:
- ValueError raised if 'protein_coding' transcripts are missing start/end codon

Bugfixes:
- Minor fixes to ensembl module and setup

Changes:
- updated setup.py

First release of EnsemblMap