Init import of VS project w/filters for files
Bunch of changes to try and get code to compile on Windows
- Converted SIZE() to GetSize()
- Added appropriate headers to yosys.h
- Made SigSpec iterators inherit from std::iterator
*** STILL DOES NOT COMPILE ON WINDOWS ***
More fixes to get things working on Windows
- Few more SIZE -> GetSize
- Added missing methods to iterators
Fixed issue with braces around for loops
Fixed for loop braces
Note: a few return statements were missing, marked with BUGBUG
More fixes for Windows
Added Windows implementation of gettimeofday
Minor fixes for Windows
Added an errors file
Init import of VS project w/filters for files
Rebased with upstream/master
Merge branch 'master' of github.com:wspeirs/yosys into HEAD

Conflicts:
	kernel/yosys.cc
	visual_studio/visual_studio.sdf
	visual_studio/visual_studio.v12.suo
	visual_studio/visual_studio.vcxproj