User manual: grammar and stylistic revision

This commit was jointly authored by Pedro Neves and Willem Ferguson.
Pedro added a FAQ section to the manual. Many long lines of text were
broken into shorter lines.

Signed-off-by: Willem Ferguson <willem@willem-Precision-M4700.(none)>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Updated user manual html file

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>