Fix conversion of PICRUSt files

Fixes #148
Merge branch 'master' into issue148
remove space from test dataset
Add scipy import check to biom.__init__.py
Changes to address @wasade comments.
updated module doc string
added Adam to credits
dropped DenseTable
_table_type is now Table.Type
dropped crazy obj hierarchy
using iteritems...
updated table_factory definition and docstring
gutted table_factory
Merge branch 'dec_flag' of git://github.com/biom-format/biom-format into dec_flag
Merge branch 'master' of git://github.com/biom-format/biom-format into dec_flag

Conflicts:
	biom/table.py
Remove test code for Dense tables
Remove SparseOTUTableTests
removed all the other table types
removed refs to _biom_type
SparseTable and constructors removed