Updates to build on Windows

* Open files with "rb" instead of "r".  On Posix, the files are always
  opened as binary but by default Windows treats them as text files.
* Use MRI's new posix4win.h to provide missing signal names on Windows.
* Add Console* implementations for Windows in main/MockDefaults.c
* Add $(QUIET) to the end of each mkdir command in the makefile.
* Update to latest submodules with their Windows fixes as well.