Remove unused

src/plugins/.gitignore

-moc_*
-*.o
-Makefile
-Makefile.Debug
-Makefile.Release

src/plugins/pixhawk_plugins.pro

-# This plugin is also identified by this line in PxMAV.cc
-# Q_EXPORT_PLUGIN2(pixhawk_plugins, PxMAV)
-
-include(../../qgroundcontrol.pri)
-
-TEMPLATE      = lib
-CONFIG       += plugin
-QT += phonon
-INCLUDEPATH  += ../. \
-    ../../../mavlink/include \
-    ../../MAVLink/include \
-    ../../mavlink/include \
-    ../uas \
-    ../comm
-HEADERS       = PxMAV.h
-SOURCES       = PxMAV.cc \
-    ../uas/UAS.cc \
-    ../GAudioOutput.cc \
-    ../comm/MAVLinkProtocol.cc \
-    ../uas/UASManager.cc
-TARGET        = $$qtLibraryTarget(pixhawk_plugins)
-DESTDIR       = ../../plugins