FMSLogo Code

Remove contradictory information.
The documentation had previously stated that BURIED output all *unburied* items.

Fix typo: "asked to bury a procedure" -> "asked to unbury a procedure"
Of course, you can't ask UNBURY to bury anything.

Fix Bug #382; WINDOWFILEEDIT no longer crashes if the file cannot be read.
Instead, it throws a file system error if the file cannot be read.
In the screensaver, it always throws the file system error, regardless of if the file can be read.

Remove trailing whitespace

Automate enough of the regression test for bug #20 to bring it into the full test pass.

Fix a bug in FILEEXISTS that caused it to return FALSE if the file existed, but was already open for reading by FMSLogo.

Replace a hack of using SETTIMER/WAIT to force a queue check with EVENTCHECK.
This is what EVENTCHECK is designed to do.

Uppercase a use of ?REST in the example.
This was done for conformance to the style guide.

Add a missing line break.
This keeps with the convention of one sentence per line.

"That is" -> "For example"
The statement introduced an instance of a truth stated by the previous sentence, instead of restating the truth in different words, so "for example" is more approriate than "that is".