Splitting global options for Win32/x64

Changes from rc5:

• Build
  • fixed sc.ini evaluation, added support for sections [Environment32] and [Environment64]
  • link dependencies can now also be monitored for the 32-bit MS linker
  • added VCINSTALLDIR to the list of available macros
  • added different options for executable and library search paths to be used for Win32/x64
  • x64: linker settings from sc.ini can be overwritten
  • x64: linker no longer invoked through dmd
• DParser
  • updated to recent version (aBothe/D_Parser@72f1bc5)
  • DParser engine now used by default if installed