This adds automatic event suppression, which works by decrementing a
token counter every time an event message is sent. When it becomes negative
an event message is emitted and further event messages are squelched
until the tokens increase above 0.

Tokens are returned (incremented) at the rate of
CFE_PLATFORM_EVS_APP_EVENTS_PER_SEC, upon the next event message call
for the app, based on time since last token return. This avoids a
dependency on HK wake messages, which are not guaranteed to be at 1Hz,
or received at all.

There are limits in place to prevent tokens from being above
CFE_PLATFORM_EVS_MAX_APP_EVENT_BURST and below
-CFE_PLATFORM_EVS_MAX_APP_EVENT_BURST. The initial value upon
registration is CFE_PLATFORM_EVS_MAX_APP_EVENT_BURST.

 * Use EVS global lock
 * Use increments of 1000 for tokens to avoid integer division
 * Use global variable instead of using platform_cfg file defines
   directly to allow unit tests to override value
 * Fix EVS event message ID

…code for events being squelched.

…kspace/phamj/CSIC9/hfi/cfe into auto-event-suppression

…rements