Added second timer to Launchpad sample.

Added a second timer to the Launchpad sample that toggles an LED at a
different rate than the first timer. Compile and runs successfully on
hardware. Also moved more timer setup code into system definition file.
Began to implement single-shot operation.
Additional tests for single-shot timer.

Added tests for verifying that a timer is started automatically upon the
Wait function being called except for when the timer is not initialized.
Also fixed the initialization check in StartTimer.