Add typographic support packages and change minimum font size

Several improvements here:

* package cmap adds a character map to the PDF to make it searchable.
* package microtype adds micro typography (margin protrusion and microscopic glyph reshaping) which improve looks and increase the quality of justification.
* Lowering the minimum font size from 6pt to 5.5pt allows the `\Cpp` logotype to appear correctly in footnotes. Currently it produces a warning and the pluses are too large.