HowTo: Switch bar to use Material Design icons

The default Regolith i3bar configuration uses fontawesome icons to display icons. It's possible to change them to whatever you like. Here we'll be updating using an optional package provided by the Regolith repositories that provide style definitions to swap fontawesome for material design icons.

1. Install the style package, which also installs the required font files:
   $ sudo apt install regolith-styles-typeface-materialdesign
2. Create a copy of the Regolith Xresource file (If you've already done this before, skip ahead):
   $ cp /etc/regolith/styles/root ~/.Xresources-regolith
3. Edit ~/.Xresources-regolith to reference the new typeface file. Comment out this line, by prepending a ! character:
   !#include "/etc/regolith/styles/typeface-sourcecodepro"
4. Add a line to reference the Material Design resource file:
   #include "/etc/regolith/styles/typeface-sourcecodepro-materialdesign"
5. Log back into the session for Regolith to pick up the changes.

Default i3bar in Regolith R1.2:

Material Design i3bar in Regolith R1.2: