[docs] significant revamp - add sphinx support

make it possible to compile documentation via sphinx - main change is to
use RST instead of MarkDown for most files.

docs/introduction.rst

@@ -0,0 +1,131 @@
+Introduction
+================
+
+General
+----------------
+bumblebee-status is a modular, theme-able status line generator for the
+`i3 window manager <https://i3wm.org/>`__.
+
+Focus is on:
+
+ - ease of use, sane defaults (no mandatory configuration file)
+ - custom modules: :doc:`development/module`
+ - custom themes: :doc:`development/theme`
+ 
+I hope you like it and I appreciate any kind of feedback: bug reports,
+feature requests, etc. :)
+
+Thanks a lot!
+
+Required i3wm version: 4.12+ (in earlier versions, blocks won’t have
+background colors)
+
+Supported Python versions: 3.4, 3.5, 3.6, 3.7, 3.8
+
+Supported FontAwesome version: 4 (free version of 5 doesn’t include some
+of the icons)
+
+Example usage:
+
+.. code-block::
+
+   bar {
+       status_command <path>/bumblebee-status \
+        -m cpu memory battery time pasink pasource \
+        -p time.format="%H:%M" \
+        -t solarized
+   }
+
+Installation
+----------------
+
+.. code-block::
+
+
+   # from git (development snapshot)
+   $ git clone git://github.com/tobi-wan-kenobi/bumblebee-status
+
+   # from AUR:
+   git clone https://aur.archlinux.org/bumblebee-status.git
+   cd bumblebee-status
+   makepkg -sicr
+
+   # from PyPI (thanks @tony):
+   # will install bumblebee-status into ~/.local/bin/bumblebee-status
+   pip install --user bumblebee-status
+
+Dependencies
+------------
+
+:doc:`development/module` lists the dependencies
+(Python modules and external executables) for each module. If you are
+not using a module, you don’t need the dependencies.
+
+Usage
+------------
+
+Normal usage
+~~~~~~~~~~~~
+
+In your i3wm configuration, modify the *status_command* for your i3bar
+like this:
+
+.. code-block::
+
+   bar {
+       status_command <path to bumblebee-status/bumblebee-status> \
+           -m <list of modules> \
+           -p <list of module parameters> \
+           -t <theme>
+   }
+
+You can retrieve a list of modules (and their parameters) and themes by
+entering:
+
+.. code-block::
+
+   $ cd bumblebee-status
+   $ ./bumblebee-status -l themes
+   $ ./bumblebee-status -l modules
+
+To change the update interval, use:
+
+.. code-block::
+
+   $ ./bumblebee-status -m <list of modules> -p interval=<interval in seconds>
+
+The update interval can also be changed on a per-module basis, like
+this:
+
+.. code-block::
+
+   $ ./bumblebee-status -m cpu memory -p cpu.interval=5s memory.interval=1m
+
+All modules can be given “aliases” using ``<module name>:<alias>``, by
+which they can be parametrized, for example:
+
+.. code-block::
+
+   $ ./bumblebee-status -m disk:root disk:home -p root.path=/ home.path=/home
+
+As a simple example, this is what my i3 configuration looks like:
+
+.. code-block::
+
+   bar {
+       font pango:Inconsolata 10
+       position top
+       tray_output none
+       status_command ~/.i3/bumblebee-status/bumblebee-status -m nic disk:root \
+           cpu memory battery date time pasink pasource dnf \
+           -p root.path=/ time.format="%H:%M CW %V" date.format="%a, %b %d %Y" \
+           -t solarized-powerline
+   }
+
+Restart i3wm and - that’s it!
+
+Examples
+---------
+
+.. include:: themes.rst
+