linalg.bench: fix imports, add svd (issue 2479), compare to numpy
Merge pull request #2508 from bburlo/linalg_bench

linalg.bench: fix imports, add svd (issue 2479)
MAINT: use Image.frombytes if available

fromstring is deprecated in python3 capable pillow
Merge pull request #2518 from juliantaylor/pil-frombytes

MAINT: use Image.frombytes if available
Made docstring more descriptive.
Merge pull request #2521 from cowlicks/descriptive-docstring

TST: sparse/test_base: Describe how the tests work
ENH: runtests: add --show-build-log option
MAINT: enable travis

Enable travis-ci. Runs the full test suite on Python 2.7, and the fast
test suite on Python 2.7 and Python 3.3.

The test suite run times are in the ballpark of:

- 10 min for the fast test suite on Python 2.x
- 20 min for the fast test suite on Python 3.x (installing Numpy is slow)
- 30 min for the full test suite on Python 2.x