FMSLogo Code

Merge in fix for Bug #537 from trunk.
(Auto-completion can now complete names that include a peroid.)

Fix Bug #537; Auto-completion can now complete names that include a peroid.
The principal part of the fix is to not use Scintilla's "is_operator", which includes '.' (and other non-Logo operator characters), but to implement a custom one for FMSLogo.

Capitalize "NULL" in a function comment.

Fix typo in CHANGELOG.TXT

Merge changes from trunk to get FILETEST.OPENAPPEND.SETWRITEPOS

Add a test that seeking a file opened with OPENAPPEND does nothing.
It's not clear that this desirable behavior, but it is what happens.

Test the interaction between DRIBBLE, PO, and Unicode.

Cleanup: Remove unused variables from FILETEST.OPENAPPEND.UTF8.

Fix DRIBBLE to encode output in UTF-8.
Prior to this, it was using UTF-16 without a BOM.

Move "-Winvalid-pch" to platform independent part of Makefile.
This prints PCH problems on Windows, in addition to on GNU/Linux.