FMSLogo Code

Add explicit tests for OPEN* procedures when the file exists or doesn't exist.

Improvements to TESTUI
- Exclud test helpers from the list
- Put each widget name within a "testui." namespace
- Add a "reload" button

Fix OPENUPDATE to work correctly with Unicode content.

Add function comment to read_character_encoding

Add a test case for reading a file encoded in UTF-16LE

Fix typo in a comment

Merge in changes from trunk (to get updates to file.lgo)

Integrate FILETEST.CLOSEALL.READERWRITER into the automated test pass by running it in a separate instance of FMSLogo.

Integrate FILETEST.CLOSEALL into the full test pass by running CLOSEALL in a separate instance of FMSLogo.

Add a simple GUI for running specific test cases