Update copyright year

And fix spaces in README
Move src/ directory to beams/

Program should be a module
Move all data files under the beams/ package
Use setuptools to install package

- Version defined in beams.__version__ (__init__.py)
- Metadata as expected
- Depend on v4+ of ETS packages
- Depend on 0.11 of SciPy because of recent pilutil fix
Look for icons as package resources

This solves the problem of where to find the icons. Now the package
depends on pyxdg.
Make entry points for camera plugins

This solves the problem of where to look for the camera plugins. They
are now all described in the 'camera_plugins' entry point of the
'beams' package. Use pkg_resources to load the entry point and get the
plugin object.

Deleted all plugin info .py files, instead the plugin info is contained
in a 'plugin_info' member in the camera class itself. The ID and
module/class names are obsolete.

This has the added benefit that if a camera plugin's dependencies are
not installed, then that plugin is simply not available through the GUI.