utility for indexing and sequence extraction from FASTA files

 fastahack is a small application for indexing and extracting sequences and
 subsequences from FASTA files. The included Fasta.cpp library provides a FASTA
 reader and indexer that can be embedded into applications which would benefit
 from directly reading subsequences from FASTA files. The library automatically
 handles index file generation and use.
 .
 Features:
  * FASTA index (.fai) generation for FASTA files
  * Sequence extraction
  * Subsequence extraction
  * Sequence statistics (currently only entropy is provided)
 .
 Sequence and subsequence extraction use fseek64 to provide fastest-possible
 extraction without RAM-intensive file loading operations. This makes fastahack
 a useful tool for bioinformaticists who need to quickly extract many
 subsequences from a reference FASTA sequence.