move crystal icons to hicolour

[Jonathan Riddell]

Currently most KDE applications have an icon in Crystal but not in
hicolour.  hicolour is the default fallback icon theme defined by the
icon standard (the name being the old icon theme used by KDE which is
now called kdeclassic).  Since KDE applications have no hicolour icons
in most cases it means they lack an icon when used outwith KDE, mainly
in Gnome's applications menu.

I'd like to move the application icons from Crystal to Hicolour to fix
this.

Jonathan Riddell