Add breakpoint support that can be set at startup

[emoon]

Ran into a big issue with this.

It seems when you supply a -moncommands to VICE and it breaks at a given breakpoint the internal VICE monitor will be brought up at the exception location. This is all fine but when one connects to VICE using the telnet connection this connection is accepted but none of the commands that is sent is being accepted by VICE.

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I have a suggested work-around for this which I really don't like but should work.

At the very start of the code, have a loop like this:

start: jmp start

This code will spin, then ProDBG will connect to VICE and issue a "n" instruction (which stops the execution) Once connected it will add all the breakpoints from the Breakpoint (JSON) file to VICE the regular way (sending the over telnet) After all the breakpoints has been sent ProDBG will patch away the loop by writing (the code will assume that the loop is 3 bytes)

nop
nop
nop

ProDBG will continue the execution.

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We can also have "patch_startup" setting in the c64_vice.cfg file that say if we should patch and add breakpoints. Without that ProDBG will just add the breakpoints as soon a connection has been made to VICE so this means that the running problem state is a bit unknown but may be fine in some cases.