Fixed KRuntime to build on mono/Linux

A Lot of changes were required to the build script, but most of the changes are just addition of if='IsMono' and if='!IsMono'. Highlights of some changes, have to add Linux directory to the nuspec folder, because the the current .nuspec files have file paths that follow windows file system structure. so i rewrite them and placed them  in the nuspec\Linux folder and directed build script to them if were are on Linux/mono and use the windows versions if we are on windows. Their is only one change in the source code which was a trivial one. I am here to answer any query about the changes i have a reason for every change.Personally tested it on both windows and Linux.
@davidfowl  i do not understand the point of this temporary hack, if move puts all the .dll and .pdb in lib of each libpackage why do we need to seperately check and move Microsoft.Framework.Project .dll ? i guess to off load some burden from the cpu, but i am wondering why does this code not break the build , when this hack code looks for a .dll that is already moved