Use a custom named tuple class IndexRecord instead of nested dictionaries for Faidx.index. Removed Faidx.rebuild_index method and refactored indexing code to remove `raw_index`.
Steaming fasta index creation. Indexing now takes constant memory.
Removed redundant data structures in Fasta class.
Utility for calculating recursive size of a container object.
Linting.
Added argparse as requirement on py26, increment version number for release.