convert tests/bench/tables to hdf5
Add dense support for from JSON
Merge pull request #311 from adamrp/add_more_dense_input_support

Add dense support for from JSON
fix name of collapse_sample_by_metadata
for real this time
Merge pull request #312 from teravest/collapsemetadata

fix name of collapse_sample_by_metadata
Merge pull request #310 from teravest/converttables

convert tests/bench/tables to hdf5
Merge branch 'backend-gutting' of github.com:biocore/biom-format into issue-290

Conflicts:
	biom/parse.py
Merge branch 'master' into issue-290
MAINT: dropping backends module
DEP: get_zerod_matrix removed
MAINT: Table.sample_ids and Table.observation_ids are now of type
np.ndarray
REL: removing backends from setup.py
REL: scipy_sparse removed from extras, hdf5 added to extras
BUG: tocsr/tocsc were being used inplace
BUG: now passing shape to csc/csr constructors
BUG: from_hdf5 was not passing type to constructor
TST: added test for Table._to_dense
TST: Add missing tests for utility functions