Added show screen syscall with screen transition support.
Added iOS support for show screen with transition syscall.
Added syscall test program for show screen with transition syscall.
Add Android support for show screen with transition syscall.
Modified comments and made small adjustments for scree transition functionality.
Merge remote-tracking branch 'sandbox/SimpleTransitions' into SimpleTransitions
Changed test program for screen transitions.
Added wrapper for the 'show screen with transition' syscall.
Added screen transition constants for WP7.
Added WP7 support for screen transitions.
Modified test program for screen transitions in order to include WP7 transitions.
Small changes to Android runtime support for screen transitions.
Small changes to WP7 runtime support for screen transitions.
Changes in comments related to screen transitions.
Changes in screen transition test application.
Changes in order to permit show with transition to be successful even if transition is not available.
Changes to WP runtime in order to permit show with transition to be successful even if transition type is not available.
Changes to Android runtime in order to permit show with transition to be successful even if transition type/duration is not available.
Added feedback in the negative duration of a screen transition parameter.
Small changes to the handling of the screen transition duration parameter.