Added correct path for mspdb120.dll for VS2013.

The mspdb120.dll file for all architectures is now stored in %VCINSTALLDIR%\bin in VS2013. I've added that path to the VC2013 path.
Merge pull request #3499 from LightBender/patch-1

Added correct path for mspdb120.dll for VS2013.
Move test case for issue 12211 to runnable/assignable.d
fix Issue 12650 - Invalid codegen on taking lvalue of instance field initializing
fix Issue 12651 - TemplateArgsOf accepts nonsensical arguments
Merge pull request #3500 from 9rnsr/fix12650

[REG2.066a] Issue 12650 - Invalid codegen on taking lvalue of instance field initializing
Fix Issue 11511 - DDoc - C variadic parameters cannot be properly documented.
Fix Issue 12653 - Implement the getFunctionAttributes trait.
Merge pull request #3501 from AndrejMitrovic/Fix12653

Issue 12653 - Implement the getFunctionAttributes trait.
Merge pull request #3502 from 9rnsr/fix12651

Issue 12651 - TemplateArgsOf accepts nonsensical arguments
Merge pull request #3503 from AndrejMitrovic/Fix11511

Issue 11511 - DDoc C variadic parameters cannot be properly documented.
Fix Issue 11819 - Implement better diagnostics for unrecognized traits.
Merge pull request #3507 from AndrejMitrovic/Fix11819

Issue 11819 - Implement better diagnostics for unrecognized traits.
refactor IntegerExp
Merge pull request #3495 from WalterBright/refactor-IntegerExp

refactor IntegerExp
implicit conversions for NewExp
Fix build on OpenSolaris.

With these changes, dmd compiles on OpenSolaris 11.1.
Fix Issue 12678 - Field constness missing in diagnostics for multiple field initialization error.
Merge pull request #3512 from redstar/solaris

Fix build on OpenSolaris.
Merge pull request #3511 from AndrejMitrovic/Fix12678

Issue 12678 - Field constness missing in diagnostics for multiple field initialization error.