Feature/3.0/more jmx os info

added a whole bunch of additional os metrics

osMemory.freePhysicalMemory
osMemory.committedVirtualMemory
osMemory.totalPhysicalMemory

osSwap.freeSwapSpace
osSwap.totalSwapSpace
os.maxFileDescriptorCount
os.openFileDescriptorCoun

os.processCpuLoad
os.systemLoadAverage
os.systemCpuLoad
os.processCpuTime

I also made the changes in the management center so that these properties are displayed.