#53 Feature: make screenshots via specified interval

[Scorpibear]

Implement possibility to make screenshots and save them to specified in configuration file directory via specified timeout.
Configuration strings:
<ScreenshotsDirectory>Screenshots</ScreenshotsDirectory>. If option is not specified, default value is 'Screenshots'.
<ScreenshotsInterval>300</ScreenshotsInterval>. If option is not specified, screenshots interval is considered 30 seconds. Time is specified in seconds.

ScreenshotsDirectory should be copied to Test Results directory (considered as FolderToCopy).
If none of the options ScreenshotsDirectory and ScreenshotsInterval are specified, screenshots should not be made. If at least one of them are specified, screenshots should be made.