Added support for uniBS

Unofficial slides for Università degli Studi di Brescia,
created for my thesis according to the official visual identity
manual.

Vít Novotný authored Sep 27, 2016 and Vít Starý Novotný committed Oct 02, 2016

Therefore, url color for light frames is no longer used in title frame.

This fixes the problem with garbled characters in PDF metadata with LuaTeX.

Base color theme now draws gradients for all (not just dark) frames.

updated the `README`.

The `make all install-base` command can now be used to perform just
a base installation. Using the `make docs install-docs` command
afterwards will typeset and install the documentation as well.