Convert numerical dtypes from strings to real types.

This only covers the simple numerical types. That is, types that have an
explicit byte order are unchanged for the moment. String types are also
unchanged.

See #823.
Merge branch 'master' into dtype-compatibility
Convert numerical dtype strings in np.fromstring.
Remove unnecessary np.dtype() calls.

Doing stuff like np.dtype(np.float32).type just returns np.float32, so
we can simplify that a little bit.
Initial version of docker based tests.
Removing redundancy and much better organization
Adding logs dir to gitignore and small bugfix
Setting node name in obspy-runtests
Ability to only build+test on certain platforms
Adding debian wheezy image.
Trigger creation of RELEASE_VERSION file.
Adding squeeze and jessie docker files.
More resilient image creation
Fixing debian jessie image.

Also the run test had a little issue.
Adding openSUSE 13.1 container
Better script organization.
Adding Readme
Use native_str() for dtype setting.
Cleaner testing if item is in a list.
Adding 32bit Wheezy image