XMLterm changes only.
Fixed xmlterm bustage due to build and nsIContentHandler changes (bug 91815).
Also modified xmlterm to handle terminal: protocol rather than telnet:,
to avoid conflict with telnet implementations (such as protozilla).
Changed xmlterm/ui/Makefile.in to use CHROME vars to handle content/skin resources (bug 34416); eliminated directories xmlterm/ui/content and xmlterm/ui/skin.
Minor tweaks to handle input of control characters. Switched to double clicks, instead of single clicks, to activate XMLterm features (to protect the user).
Improved full screen implementation; added bold and underline styles. Centralized UI event handling. Added checks to limit number of output lines displayed. Added capability to interrupt hung output data streams. Nearing full backwards compatibility with xterm.
Implemented full screen operations in XMLTerm, although still buggy.
Commands like 'less', 'vi', and 'emacs -nw' now work in stand-alone xmlterm,
although scrolling is still messed up. Compiles with Feb21 tree.
