Revert "appDisplay: Special case terminal launching"

Having terminal launchers behave differently than any other launchers
is non-obvious and confusing. Remove the special-casing to restore
consistency, we will make the new window action more accessible
instead.
This reverts commit 68faba6bde08a8898941, 4ed0f3e5f0f9d2f7
and 887a21afb97aaa35.

https://bugzilla.gnome.org/show_bug.cgi?id=695010
appDisplay: Open new window on middle-click

The current middle-click action of opening a new window on a new
workspace is a bit peculiar; it is also not overly hard to achieve
the same result by moving a new window to the desired workspace or
selecting a workspace before opening a new window. Just opening
a new window is also a more common action, so having a shortcut
available that doesn't require a modifier is a good idea as well;
change the middle-click behavior accordingly.

https://bugzilla.gnome.org/show_bug.cgi?id=695010