Document the droptect plugin
Document the droptect plugin

Summary: Closes T85.

Test Plan:
Besides adding comments and Latex docs, the code has been shortened,
variables have been renamed, const has been added,
for better readability and documentation.  Functionality should be unchanged,
please check during review.

droptect section in PDF built by Jenkins should be checked. {F10445}
contains a sample config using droptect. @tobias will test this on a Beaglebone.

Reviewers: pmaanen, hendrikk

Reviewed By: pmaanen

Maniphest Tasks: T85

Differential Revision: https://dev.openmha.org/D228

HoerTech-gGmbH/openMHA,HoerTech-gGmbH/openMHA,HoerTech-gGmbH/openMHA,HoerTech-gGmbH/openMHA,HoerTech-gGmbH/openMHA,HoerTech-gGmbH/openMHA,HoerTech-gGmbH/openMHA,HoerTech-gGmbH/openMHA