Include Travis CI build status in README.rst
Remove dependency on numpy

Closes #17.

The dependency was merely a convenience and functionally not necessary. By
removing it we gain pypy compatibility and make the package more light-weight
in general.
Implemented neq for vector and corrected eq
Implement hash for vector.
Test hashing of vector.
Merge pull request #31 from Moredread/moredread/feature/vector_hash

Moredread/feature/vector hash
Merge pull request #27 from aepsil0n/doc/readme_travis

Include Travis CI build status in README.rst
Merge pull request #30 from Moredread/moredread/fix/add_neq_and_fix_eq

Implemented neq for vector and corrected eq
Fix implementation of PolarGrid2D

The breakdown of this class under the transformation was due to missing
regression tests, which have been added now. Its behaviour has been documented,
too.

To run the test suite on Python 2.6, it was necessary to hack a monkeypatching
mechanism for absent assertions in `nose.tools`.
Merge pull request #26 from aepsil0n/feature/rm_numpy

Remove dependency on numpy