A small set of example programs

tkSend and xmSend
-----------------
These each display a button. Pressing on either one sets a message in the 
other.

tkSend2 and xmSend2
-------------------
These each display a button. Pressing the Tk button increments the label
in the Motif button. Pressing the Motif button sets the label in tkSend
(if it is still running)

tkSend3 and xmSend3
-------------------
These each display a count in a button. Pressing either one increments the
other, which sends a message back to increment it, etc (recursive sends).

tkSend4 and xmSend4
-------------------
xmSend4 sends messages to itself to increment counters, and also to tkSend4

xmSend5
-------
Creates three tcl interpreters and registers them with different names.
Sends messages to one, two or three of these interpreters.

xmSend6
-------
List all currently known interpreters.