Netperf

Add netperf class as base class.

dd netperf class as base class.

Support netperf client in windows guest.

Support install parameter to control whether install netperf or not.

Please put shared/deps/netperf/netperf-2.6.0.tar.bz2  netserver-2.6.0.exe   to tp-qemu/deps/netperf/ folder.