Cleanup warnings and LinuxJedi's docs

Cleanup warnings and LinuxJedi's docs

This branch:
* Adds information on modifying the systemd script provided in
  boot_scripts
* Adds documentation for the newest options on the PiStorm gui
* Fixes a memory leak and a potential crash on alloc failure for the gui
* Minor text changes in the gui
* Fixes minor compiler warnings for the PiSimple CLI (both for GCC and
  VBCC)