Problem:    Crash when wiping buffer in a callback.
Solution:   Do not handle messages when only peeking for a character.
            (closes #2107)  Add "redraw_flag" to test_override().

Problem:    MS-Windows: VTP doesn't work properly with Powershell.
Solution:   Adjust the color index. (Nobuhiro Takasaki, closes #3347)

Problem:    Reverse order of VTP calls only needed the first time.
Solution:   Add a flag to remember the state. (Nobuhiro Takasaki, closes #3366)

Problem:    MS-Windows: tests fail, Vim crashes.
Solution:   Fix long file name handling.

Problem:    MS-Windows: sometimes uses short directory name.
Solution:   Expand to long file name with correct caps. (Nobuhiro Takasaki,
            closes #3334)

Problem:    Saving and restoring window title does not always work.
Solution:   Use the stack push and pop commands. (Kouichi Iwamoto,
            closes #3059)

Problem:    MS-Windows using VTP: windows size change incorrect.
Solution:   Call SetConsoleScreenBufferSize() first. (Nobuhiro Takasaki,
            closes #3164)

Problem:    v:shell_error is always zero when using terminal for "!cmd".
Solution:   Use "exitval" of terminal-job. (Ozaki Kiichi, closes #2994)

Problem:    MS-Windows: missing #endif.
Solution:   Add the #endif.

Problem:    $VIM_TERMINAL is also set when not in a terminal window.
Solution:   Pass a flag to indicate whether the job runs in a terminal.