Notes:
* Given permission to change System settings (such as screen brightness).
* Settings menu. Now it saves and updates according to the preferences of the user.

TO DO:
1. Activate hardware components (GPS, Wifi) according to the user preferences for the test. (High priority, but complicated).
2. Implementation of the 2 Pi algorithms for CPU Benchmark (High Priority and dependendent on N.1)
3. Small "about" section (Low priority, but easy).
4. Small tutorial section (Low priority, but easy).
5. Give more options to the user, prompts explaining what each option does (Low priority, dependent on N. 1 and 2).
6. Some refactoring may be needed (Low priority).

Signed-off-by: Javier López Lumbreras <loplumja@hotmail.com>