* core.c (dis_asm_read_memory): Add call to
dis_asm_read_memory_hook to provide alternate way for disassembler
to read memory.
* defs.h: Protect from multiple inclusion. Add decl for
dis_asm_read_memory_hook.
* gdbtk.c (finish_saving_output): Don't do anything if not saving
output.
* (breakpoint_notify): Don't send null filename to tcl.
* (gdb_eval): New tcl command to eval an expression.
* (gdb_disassemble): New tcl command to do disassembly. This
allows tcl code to choose between exec file and target memeory,
and can also do mixed source and assembly.
* (gdbtk_init): Move reading of gdbtk.tcl to the end to make sure
that more of the environment is set up. Also, create link between
gdb and tcl vars disassemble{-_}from{-_}exec.
* gdbtk.tcl: New expression window support.
* Make assembly window be 80 columns wide.
* Use new disassembly method. Add menu items to select
disassembly from exec file or target.
* Change View menubar item to Options.
* Get rid of Stack, Breakpoints, Signals, and Variables Windows,
since they don't exist yet.
* Pop up a copyright window on startup.
* top.c: Make window startup be the default.
* Add dis_asm_read_memory_hook.