More tests for composition calculation + refactoring for ease of testing
Use Counter for faster kmer counting
Do kmer in feature_mapping check later, and fewer times
Use kmer tuple instead of string for speedup
Do length filtering early, refactoring input
Speedup using numpy for counting kmers
Merge pull request #105 from alneberg/optimize_input

self.merge()
Fix issue #106, pca dimensions logging
Merge pull request #107 from alneberg/fix_pca_report

Fix issue #106, pca dimensions logging, self.merge()
Bumped version to 0.4.0
Merge pull request #108 from alneberg/develop

Bumped version to 0.4.0
Merge pull request #109 from BinPro/develop

Release version 0.4.0