vs2012 toolchain: various fixes

Fixed 1.8 compatibility

fix build faild on Cygwin Environment

CC: / instead of - (cosmetic change)
LD: removed default libraries and fixed options syntax
AR: added /nologo

Adapt Compile Documentation to improved Build process

Beautify build process output

Improved build scripts and config files

Modify handling of NODE_UNDEF.

Modify handling of quoted non-expanded string literal

Modify handling of `bodystmt`.

Modify handling of OP_ENTER.

If `argc` is `-1`, `block` parameter is sometimes overwritten.

Clear all old flags, even if we change the gc mode during the major gc.

Fix disappearance of command_call in case of statement without parentheses

supress cast warning on C++.

Use new mrb_get_args binary specifier.