Merge pull request #5 from chrispetsos/GPII-153_GPII-187

GPII-187: Working with composite panels with few problems
GPII-153, GPII-187: Created a wrapper stepper class gpii.adjuster.textfieldStepper and applied it to PMT and PCP. This leads to the removal of plusMinus component in PMT code.
GPII-153, GPII-187: Break down increaseSize.json to several message json files for every sub-panel.