RFR 8147984: WindowsTerminal should support function keys

[Jan Lahoda]

Hello,

I'd like to enhance the WindowsTerminal in jdk.internal.le with function 
keys handling. The intent is so that jshell can bind actions for 
shortcuts including function keys.

The patch for adding the function keys support is here:
http://cr.openjdk.java.net/~jlahoda/8147984/webrev.00/

An example of a feature that uses/may use this support is here:
http://mail.openjdk.java.net/pipermail/kulla-dev/2016-January/001226.html

Any comments are welcome!

Thanks,
    Jan