Add support for VS2012.

Factored out common VS code into msvc-vscommon.lua
Fix Win32 64-bit bootstrap build error.
Some minor fixups so it builds on Mingw
Fixed unresolved symbol min when building under Mingw
Added some build flags for Mingw
Added win32-mingw to tundra's build file so Mingw can be used.
Merge pull request #141 from greatwolf/master

Fixups for  Issue #140 Mingw support
Fix spaces in TundraExePath when generating MSVC IDE projects
Merge pull request #148 from Drakonite/master

path fix for MSVC ide support
First public checking of 2.0 beta branch.

Summary of changes from 1.0:
- Switch from MD5 to SHA-1 hashing
- MD5 file digesting is gone (too slow for big projects)
- Unit tests for core functionality
- Switch to C++ implementation
- Lua frontend is only invoked when needed
- Lua environemnt interpolation in C++ code
- Native build system uses fast mmap()d data structures
- Vastly improved MSVC project generation.
- Bootstrap build with Makefile or vs2012 projects

Null builds with 10k+ source files typically run in 200 ms using this
new design as the Lua frontend is completely bypassed when not needed.

Still lots of stuff to do, see doc/todo-2.0.txt and grep for TODO/FIXME.
Merge branch 'master' of https://github.com/deplinenoise/tundra
The BSDs use stdlib.h for alloca(), wrap appropriately.
Build dependency files while building object files

Instead of building dependency files separately use the compiler's -MD
option to build both concurrently. This speeds up the initial build
considerably.
Move TODO list to github issues.
Create unique names for dummy nodes.

Closes GH-152.
Fix generic include scanners (asm)

This makes the 15 original tundra tests run without failure again.

Closes GH-154
Track opened/read files internally in Lua.

Fixes GH-158
Windows: Remove Win32 config. Link statically with CRT.
Quote path to t2-lua if needed (spaces)
t2-inspect: Dump env vars too.