Add support for grid mappers with fixed aspect ratios.
Add fixed aspect ratio example.
Cleanup imports.
PEP8-ify (although I refuse to put spaces arounf '/' and '*' operators :)
Merge pull request #129 from enthought/feature/fixed-aspect-ratio

Add support for grid mappers with fixed aspect ratios
Fix a KeyError from del_data introduced in PR #124.  Add minimal tests for ArrayPlotData.
Merge pull request #131 from enthought/fix-del-data

Fix a KeyError from del_data.
Adding travis-ci config file.
Adding traitsui from master.
Adding a before install script that sets ETS_TOOLKIT to avoid traitsui errors.
Adding commands before install script to avoid pyqt errors.
Adding code to install PyQt only for python 2.7.
Try removing PyQt altogether for all versions.
Try turning pyqt install on again with an additional qt-gl package.
Adding more packages to the list for installing qt4.
Typo in travis yaml file.
Typo2 in travis yaml file.
Adding a changelog file.
Running only a subset of tests for python < 2.7. Adding version 2.5 to see how we are doing there.
Moved 2 test modules to a new folder chaco/tests_with_backend so that others can be run separately on Travis CI.