Makefile and template updates

* Adds makefiles for the Jupiter Ace
* Moves Z80 and MCS48 and EMUDUMMY into a common makefile
* Adjusts the Cat and Coleco builds to use that common makefile as examples
* Updates the build parameters for IBM 5150
* Changes messloader.js to be usable for testing by removing the .gz filename which the Python test server doesn't support, and by supporting systems which don't require game files to boot