merge build_vs2012.bat into build.bat

Choose compiler with VS2012 and VS2010 switches.
Defaults to VS2010 if omitted.

Merge based on build_vs2012.bat and gccbuild.bat by XhmikosR
Merge pull request #39 from m0vie/scripts
Allow files to be dropped onto run_astyle.bat for styling
remove unneeded variables
coverty.bat: use VS2010 for now
update docs/Todo.txt
update contrib/icl13.diff