fix struct generation
Update to Visual Studio 2013.
This commit changes several things:
 - Solution and project files are now compatible with VS2013
 - Upgrade FSharp.Core to version 4.3
 - Remove dependency on the fsyacc and fslex from the old PowerPack
 - Add dependency to the FsLexYacc NuGet package
 - Add auto-download of NuGet package
 - Add compile rules to build parse.fsy and lex.fsl automatically
ocaml backend: support for primitive operators
starting to revive SMT encoding
Update Makefile to use NuGet to fetch FsLexYacc
With this change, cygwin and mono users will be able to automatically download fslex and fsyacc, removing the dependency on the old PowerPack on all platforms
OCaml backend: fix tuple generation
Merge branch 'VS2013' of git://github.com/ad-l/FStar into ad-l-VS2013
Fix build under mono + update INSTALL
Merge branch 'ad-l-VS2013'
tweaks in tosmt; checkpoint before merging with VS2013 branch
merged with VS2013
auto-changes to sln by VS2013 for compatibility with older versions
adding ref for VS2012 compat
slow progress/cleanup in tosmt
Add rules for using msbuild (xbuild).
Precision to compile under Linux
merged Makefile
moving things out of the poorly named examples/unit-tests directory; turned the --pretype flag on by default
missed a file
populating the exports of a module based on its interface, if any; have not added private qualifiers yet (TODO)