Bugfixes and stability improvements

This update should greatly improve stability:

• Removing several sources of hardfaults, mostly related to timeslots.
• Dropping updates to the database if an event can't be propagated, so that the update can be processed later, when the event queue becomes available.
• Removing an overflow on mesh payload-search of packets without payload (this issue would make it look like the mesh gets updates to handle numbers you've never seen before).
• Enforcing limit on application-handles - all handles over 0xFFEF are reserved system handles for future mesh maintenance and the upcoming DFU feature.
• Increased default packet pool size to allow all queues to fill completely without overflowing.
• Moved all default size-#defines to rbc_mesh.h, making it easier to configure memory to fit your applications.
• Fix for Issue #52.

So no new functionality for this one, but this release fixes all crashes and any odd behavior we've been able to identify in our tests since v0.7.0.