This introduces the following changes:
* Fixes libPrefix in Tcl libraries I fucked up a few months ago and adds
missing meta attributes.
* Correctly set TKABBER_SITE_PLUGINS so Tkabber is able to find plugins, if
present.
* Rely on OPENSSL_X509_CERT_FILE instead of depending on cacert directly.
* Introduces a new license called "Tcl/Tk", which applies to some Tcl libraries
and is a variation of the BSD license with restrictions regarding
governmental use.
* New package tclgpg for GPG support in Tkabber.
