missing binding for virUUIDParse

binding for the C API: virUUIDParse() is missing.

Functions like:

func (c *Connect) LookupDomainByUUID(uuid []byte) (*Domain, error)

require a byte slice of 16 bytes,

so one still needs to convert uuid values that come from XML strings containing the alphanumerical representation of those bytes intermixed with '-', to the clean 16 bytes byte slice.