Handle extended key codes
Make sure ShowCaret/HideCaret calls are always balanced
ConsoleReadCh reads a char from console and maps it to a gnuplot code
Test for qt != NULL
cairo/pango terminals can be included in build without wxt
Build qt files out of tree. Support Qt5. Install gnuplot_qt.
Required libraries may be installed in a common directory structure
Make the install target more similar to the one in mingw/Makefile
ConsoleReadCh reads a char from console and maps it to a gnuplot code
If not enough data is available via the socket from gnuplot_qt, warn and continue rather than spinning futilely