data_* -> data
Merging upstream master
Merge pull request #336 from josenavas/data

Data
TST: fixing test_add_metadata_one_w_existing_metadata
Merge branch 'fixconstructor' of https://github.com/teravest/biom-format into fixconstructor
TST: all tests pass
Merge branch 'master' of https://github.com/biocore/biom-format into fixconstructor