Introduction of settings page, minor refactorings to accomodate

Refactored the settings class to reduce the effort it takes to add future settings. Created the TimeoutPeriod setting in order to keep track of user defined timeout period instead of hardcoded value. 

Created settings page with a control to adjust and persist this setting. Replaced all hardcoded instances with look-ups to setting.

In order to facilitate the NumericUpDown control, I added the WinRTXamlToolkit nuget package from codeplex.