Problem:    Can't distinguish <M-a> from accented "a" in the GUI.
Solution:   Use another way to make mapping <C-bslash> work. (closes #6163)

Problem:    MS-Windows: exepath() works different from cmd.exe.
Solution:   Make exepath() work better on MS-Windows. (closes #6115)

Problem:    BeOS code is not maintained and probably unused.
Solution:   Remove the BeOS code. (Emir Sari, closes #5817)

Problem:    MS-Windows: the Windows terminal code has some flaws.
Solution:   Do not redraw the right edge of the screen.  Remove the background
            color trick.  Flush the screen output buffer often.  (Nobuhiro
            Takasaki, #5546)

Problem:    Typval related code is spread out.
Solution:   Move code to new typval.c file. (Yegappan Lakshmanan, closes #6093)

Problem:    Build failure with small features.
Solution:   Add #ifdef.

Problem:    Text properties crossing lines not handled correctly.
Solution:   When joining lines merge text properties if possible.
            (Axel Forsman, closes #5839, closes #5683)

Problem:    Text properties crossing lines not handled correctly.
Solution:   When saving for undo include an extra line when needed and do not
            adjust properties when undoing. (Axel Forsman, closes #5875)

Problem:    Filetype elm not detected.
Solution:   Recognize *.elm files. (closes #6157)

Problem:    MS-Windows: channel tests fail.
Solution:   Adjust #ifdefs. (closes #6162)