#85 Export control - file based instead of project based

[Earnie Boyd]

The MinGW project offers many files for download. Only a small few of those files should be affected by the export control. I would like the option of removing the need for export control at the project level and add it at the file level. To implement I would leave the project level export control but add it to the files level so that projects whose files should always contain export control can turn it on at the project level while projects like MinGW would turn the project level export control off and turn it on for the files like OpenSSL which should be controlled.