[Bug-apl] ⎕PW handling

[Juergen Sauermann]

Hi Alexey, Kacper, I have made some changes related to ⎕PW in SVN 830. Alexey: you can now also specify the inital ⎕PW in your preferences file(s) instead of on the command line. Kacper: you can now enable change of ⎕PW via the WINCH signal. This may not work on all platforms, therefore is has to be enabled in one of your  preferences files. /// Jürgen