Adds PalmBus Subscription Tests

First test subscribes to luna://com.palm.systemservice/getPreferences for showAlertsWhenLocked, then uses setInterval to repeatedly change it.  It thus continues to call setPreferences regardless of whether the subscription is still working.

Second test subscribes to luna://com.palm.wifi/findnetworks, which emits updates at variable intervals, but on the order of 10s.  When called from luna-send, it emits updates indefinitely.

Third test calls luna://com.palm.db/find with watch:true. This immediately returns results, and should later return a single NotificationResponse if the results change. It does not return repeated updates like getPreferences.   When find results are returned, the test uses setTimeout to later put another object to DB8.  This should trigger the NotificationResponse.  When a NotificationResponse is received, the test issues another find.  Thus, if/when the NotificationResponse is not received, the cycle is broken and no more objects are put.

Open-WebOS-DCO-1.0-Signed-Off-By: Doug Reeder <reeder.29@gmail.com>