fixed a typo in the docstring of Database.add
Merge pull request #716 from derdon/dbdocs

fixed a typo in the docstring of Database.add
hypermap & coordinate_system prototype
Hypermap to HyperMap
HyperMap update
test_iris.py newline fix
Added support for Spectral + some error checking.
added pixel_size and number_of_pixels to CoordinateFrame