#2 font handling improvements

[Emiliano]

Attached patch improves the overall text handling in the rbc::graph widget by using native Tk functions. See
http://groups.google.com/group/comp.lang.tcl/browse_thread/thread/e897bc27f9dc66bb/41defdf6a2ca0b39
for details. It also removes direct access to interp->result, allowing it to build against Tk 8.6.
For Tk 8.6 newer than 2010-12-02, the HAVE_ANGLEDTEXT define allows full text
internationalization / rotation (thanks to Donal Fellows for writing the code and moving
the relevant functions to the internal stubs table).
With the patch applied all relevant test pass.
All work/tests were done on a linux machine.

[Emiliano]

font handling patch

[Emiliano]

Oops. Forgot to change font defaults to saner values when HAVE_ANGLEDTEXT is defined.