ENH: creation-date and genoerated-by now stored in Table
Remove check for file before write

Fixes #274.
ENH: Add h5py version and remove backend info

This information has been removed from the string displayed in:

    $ biom show-install-info

The information now looks like this:

    System information
    ==================
    Platform: darwin
    Python/GCC version:   2.7.6 (v2.7.6:3a1db0d2747e, Nov 10 2013,
            00:42:54)  [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]
    Python executable:
    /Users/yoshikivazquezbaeza/.virtualenvs/biom-dev/bin/python

    Dependency versions
    ===================
    pyqi version:   0.3.1
    NumPy version:  1.7.1
    SciPy version:  0.13.3
    h5py version:  2.3.0

    biom-format package information
    ===============================
    biom-format version:   1.3.1-dev

In case h5py is not installed, it will look like this:

    System information
    ==================
    Platform: darwin
    Python/GCC version:   2.7.6 (v2.7.6:3a1db0d2747e, Nov 10 2013,
            00:42:54)  [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]
    Python executable:
    /Users/yoshikivazquezbaeza/.virtualenvs/biom-dev/bin/python

    Dependency versions
    ===================
    pyqi version:   0.3.1
    NumPy version:  1.7.1
    SciPy version:  0.13.3
    h5py version: WARNING: Not installed - this is an optional dependency.
    It is strongly recommended for large datasets.

    biom-format package information
    ===============================
    biom-format version:   1.3.1-dev

Fixes #360
Merge branch 'master' of github.com:biocore/biom-format into other_attrs

Conflicts:
	biom/table.py
Merge pull request #371 from ElDeveloper/issue-360

ENH: Add h5py version and remove backend info
ENH: Add with and without H5PY tests in travis.yml

DO NOT MERGE.

Fixes #288
REL: biom deps on pyqi 0.3.2 now
Merge pull request #356 from wasade/other_attrs

ENH: creation-date and genoerated-by now stored in Table
Change function call to "to_json"
MAINT: removing unused methods
ENH: passing shape now to dict_to_sparse
MAINT: removing unused imports
ENH: Remove h5py on USE_H5PY=False
API: summarize-table no longer can do md5
STY: line to long
ENH: Uninstall h5py after pip installs it
ENH: Uninstall h5py using pip instead of conda
STY: Group together the conditional statements.
poop
Merge pull request #374 from wasade/issue_272

Issue 272