Minor patch regarding CommandTask priority

Changed CommandTask priority from osPriorityNormal to osPriorityBelowNormal. This is how it was at the RoboCup competition.

RoboCup 2018 with minor changes

This release contains the software used during the 2018 RoboCup competition. Major modifications post-RoboCup are as follows:

• Software is nearly fully-documented using Doxygen
• Several minor bug fixes
• IMU DLPF setting is 6 instead of 4
• IMU thread is now time-triggered and gyroscope data is digitally filtered
• Cube now generates extern declarations of task functions instead of stub implementations

Furthermore, this release contains significant progress in the development folder with regards to foot pressure sensors and Ethernet communication.