Basically, tbuisp was checking if a file was an exe or srec based on
extension.  This was failing when tbuisp was invoked from xmlrpc, because
the rpc server created a temp file without a .exe extension.  Thus, tbuisp
thought that the file was an srec (since it wasn't an exe)... and motes
were not getting programmed properly.  tbuisp now distinguishes which type
the file is using avr-objdump, and matching the format.  The downside of
this is that we'll need to support different kinds of exe binary types as
we add different kinds of motes (i.e., the binary type for our avr-based
motes is elf32-avr... surely the telos motes will have a different type).