FMSLogo Code

Refactoring: restructure open_file to remove duplicated code.
Also add comments and reduce the scope of th WX_PURE block.

Add regression tests that SETREAD and CLOSE are case-sensitive for the reserved filename "clipboard", even though it can be opened with any case.

Add regression tests that SETREAD/SETWRITE/CLOSE must exactly match the file name.

Replace some RUNBADINPUTTEST with RUNDOESNTLIKEINPUTTEST.
RUNBADINPUTTEST is deprecated because it doesn't check the error code.

Add regression tests for reading from the clipboard with OPENREAD "clipboard

Fix a typo in a comment "contruct" -> "construct"

Branch the 7.5.0 release to start work on Unicode.

Tag the source code that was used to build FMSLogo 7.5.0.

Update with test results from the 7.5.0 test pass.

Increment the version to 7.5.0 for a formal release