Adding checking for _M_ARM macro for Windows.
Incorporating feedback from Rene Rivera:
Updated the Microsoft copyright to include the year.
Made sure ARM predef uses version property with V.0.0.
Merge pull request #4 from MSOpenTech/windowsarm

Adding checking for _M_ARM macro for Windows.
Addressing feedback from Rene Rivera for adding BOOST macros for detecting the Windows Runtime being targeted.
Now there are new predefs for desktop, store, phone, and the Windows Runtime (store/phone) in general.
These can easily be used throughout Boost to detect the Windows platform being targeted.
Adding missing newlines at the end of a few files.
Merge pull request #5 from MSOpenTech/winrt

[winrt support] Adding predefs for testing and checking the Windows Runtime being targeted.
Fix BOOST_PLAT_WINDOWS_* defs being defined on non-Windows systems.
Add platform defs section to docs.
Update documentation to current basic source state.