porting initial code for RamUsageEstimater, SystemProps, Constants and HashMap. Changing the portable library version to use .net 4.5.1 in order to use the pcl version of Microsoft.Framework.Configuration.
porting initial code for RamUsageEstimater, SystemProps, Constants and HashMap. Changing the portable library version to use .net 4.5.1 in order to use the pcl version of Microsoft.Framework.Configuration.