Add quirk POSIX Extended Regular Expression pattern matching.

Add quirk POSIX Extended Regular Expression pattern matching.
Note that square brackets [] and colons : in patterns must be
escaped with a backslash \ in addition to any other escaping.

Add 3rd (optional) _NET_WM_NAME/WM_NAME field to quirks.
Quirks can be specified as quirk[<class>], quirk[<class>:<instance>]
or quirk[<class>:<instance>:<name>].
The 'instance' and 'name' fields are optional and will 'match all' if
omitted or 'match empty' if left blank.

Cleanup window property terms; should be 'class', 'instance' and 'name'.
title_class_enabled and title_name_enabled are now aliases for
window_class_enabled and window_instance_enabled, respectively.

Fix uniconify of windows having neither _NET_WM_NAME nor WM_NAME.

Use const in conf_load functions.