Changed the default theme and added a light one
Themes are modified versions of 'solarized_light' and 'slate' from https://github.com/gmate/gmate/tree/master/styles,
released under LGPL.

Closes #30
Added a status bar
Re-enabled (still buggy) completion
Completion update. Still buggy
Completion: re-enabling only in debug mode
Showing type of library function under cursor in status bar using ocp-index
Better status messages