classes for network adapters and block devices
bump java compiler version compatibility to 1.6
fixing adapter class
simple junit test
missingfieldexception and other changes
importing https://github.com/justnom/pve2-api-java/commit/48194e6ff78203ab62e66381bc576f70aa98f82c#src/main/java/net/elbandi/pve2api/Pve2Api.java