Added virConnectGetLibVersion binding
Mapped virDomainCreateXML and its flags
Provide VIR_DOMAIN_MEMORY_PARAM_UNLIMITED constant
Mapping for errors

Changed GetLastError to return VirError instead of a simple string.
VirError helps getting easy access to the error code, level and domain.
VirError implements the error interface for easy use.
Comment out VIR_ERR_CPU_INCOMPATIBLE
Added in 1.2.6, not available in 1.2.4
Domain events API implementation

The big amount of callbacks from libvirt C API has been mapped to
different details structs in the Go API.
Avoid libvirt outputting to stderr
Added VirDomain.GetID()

(@alexzorin, go fmt)
Allow nil uri in NewVirConnection*

Closes #38
Remove test for TestConnectionNilUri
Shim for VIR_FROM_BHYVE,VIR_FROM_CRYPTO,VIR_FROM_FIREWALL

Since we are rolling back support in #40 from libvirt 1.2.4 to 1.2.2,
I am introducing shims for these constants that are not
available in 1.2.2. Hopefully won't break.
Test environment now FC19 with libvirt 1.2.2

As part of #40
Update README to reflect #40 changes

Closes #40
add VirDomainInterfaceStats

@alexzorin: fixed build error and added integration test
closes #41