overhaul events subsystem: API changes, ghashtable split for reg/mem events, signal handler in example and various bugfixes and improvements
Merge pull request #56 from Zentific/events

Update Xen Events
Events : add MSR write monitoring capability
Events : Initialize events in VMI_INIT_PARTIAL mode (so MSR, CR0, CR4 can be observed in addition to memory page events without needing to wait for the conditions necessary for VMI_INIT_COMPLETE)
Events : add some notes on MSR writes observed for a few OS versions and their values.
Events : ensure that LibVMI is in a sane state before event setup for full init.
Merge pull request #58 from smaresca/msr_events

Events: add MSR write monitoring for Xen
fix xen domain id comparison types
Merge pull request #59 from Zentific/xen_domid_fix

Fix xen domain id comparison types