Minor improvements

Minor UI improvements

English Language modules: Bugfix at Custom Settings menu

Bugfix at evaluation of Rotating Cube test

Strip Display Management Test: Bug fix at evaluation of test results

Minor bug fix at Matching Figure Test

Minor bug fix at Memorize Pictograms test

Bug fix at Memorize Pictograms test

Radar Control Test: caching at control panel

English language skills: English version of Idioms module added

Minor bug fix at Radar Control Test

Spot the Side test: Hexagon added

Minor bug fix regarding virtual keyboard

New preparation modules:
- Matching Figure Test
- Multi Attention Test

New test: Radar Control Test

Minor improvements