Pyfaidx

- --delimiter option for cli script and split_char argument for Fasta
and Faidx

- --split-files option writes each returned sequence to an individual
file. Names are generated based on the sequence name and region
coordinates.
- --stats option prints the name and sequence length for each entry,
suitable for use as a UCSC-style
[chrom.sizes](http://genome.ucsc.edu/goldenpath/help/hg19.chrom.sizes)
file.
- Sequence longname attribute allows access to "chr:start-end
(complement)" formatted names

- Fasta __getitem__ no longer initializes new FastaRecord classes
- Faidx read_ahead attribute implementaion avoids unnecessary disk
hits ([34](https://github.com/mdshw5/pyfaidx/issues/34))

- Fasta can now accept an integer index in addition to string keys.

- FastaRecord now works as a line-based iterator
([30](https://github.com/mdshw5/pyfaidx/issues/30))
- Added MutableFastaRecord class that allows same-length in-place
replacement for FASTA
([29](https://github.com/mdshw5/pyfaidx/issues/29))

- Added read-ahead buffer for fast sequential sequence access
([26](https://github.com/mdshw5/pyfaidx/issues/26))
- Fixed a condition where as_raw parameter was not respected
([27](https://github.com/mdshw5/pyfaidx/issues/27))