This is going to be a bit more comprehensive than anticipated. In order
to cleanly refactor the core and the engine, basically start from
scratch with the implementation.
Goals:
* Test coverage
* Maintain backwards compatibility with module interface as much as
possible (but still make modules easier to code)
* Simplicity
see #23
Hide alias concept for modules in the engine. That way, the individual
modules never get to know about whether a module has been aliased or
not.
see #23
Big oversight in my previous commits: Widgets need to be able to have
specific configurations (i.e. the path for different instances of the
"disk" module has to be different).
To account for that, it is now possible to assign an "alias" to a module
instance using ":" (for example: -m "disk:home"). This alias is then
used for the configuration parameter resolution automatically, for
example:
-m disk:home -p home.path=/home
As a consequence, parameter names in the module code are now relative to
the module, which means: shorter!
* cpu+memory: Open "gnome-system-monitor"
* disk: Open nautilus
* pulseaudio: Mute/unmute, open "pavucontrol" on right-click, raise/lower
volume on mouse wheel up/down
Pass the "output" object to the modules' constructor to allow them to
define their own callbacks.
Any user-provided callbacks take precedence and override those of the
module.
Add a module that retrieve mute status and volume (left, right, mono)
from pulseaudio. Unfortunately, this module is really, really hacky. It
invokes "pactl" multiple times to get the status and does some ugly
parsing on the output.
Overall, this is pretty brittle and prone to failure, but as I was not
able to find a decent pulseaudio library for Python... Probably, I
haven't searched hard enough, cannot believe such a thing does not
exist.
