prep for xpd
Merge branch 'release' of https://github.com/synapticon/sw_sncn_motorcontrol_ethercat_kit into release

* 'release' of https://github.com/synapticon/sw_sncn_motorcontrol_ethercat_kit:
  adding README.rst and removing not needed docs
  adding missing image file extention in the doc
  Convert doxygen style license file to plain txt
  adding app_demo_bldc_position quickstart guide
fixed :boards: tags in READMEs ato mention the XMOS kit part numbers, plus xpd prep
xpd update
removed link to external image from toplevel readme and added SOMANET keyword to readme titles
added CHANGELOG