[Qt-creator] Opening files

[Robert Caldecott]

It would be useful if I could open files using the correct registered
application from Qt Creator.

For example, I have a Windows project that includes an Inno Setup
script (a file with a .iss extension).  I have added this file to the
project but when I double-click on it it opens in the Qt Creator text
editor - it would be useful to be able to right-click on the file and
select 'Open With...' and then see the application that is actually
registered for the file extension (in this case the Inno Setup IDE).

Eventually it would also be nice to be able to create build rules for
non-standard files like this so I could right-click on the file and
compile it - an option that allows you to specify the command-line to
run, etc, would be useful.