Implement a generic "load keywords and replace during runtime"
mechanism, with the first concrete use-case of WAL colors (load them
during startup, and during runtime, whenever a matching name is found in
the keywords, replace with the actual color)
Add states to the modules and widgets. Widgets are mostly just a
pass-through (backwards compatibility, and ease of use - making states
directly inside the widgets would require more code inside the modules
to ensure that each widget is correctly updated).
Still missing:
- Separators during partial update (right now, it takes one interval
until separators are drawn correctly)
Add a way for themes to specify custom separators. Doing that, make
nicer interfaces for drawing "supplementary" components (separators)
for widgets and generalize the attribute retrieval within the theme.
Add two new parameters: theme and iconset
Add a placeholder class core.theme.Theme, an instance of which is passed
in to the i3 output object (which is the only object that should ever
have need of the theme, hopefully).
