Improve the debugger

[tomhea]

Add the following options:

• breakpoint only on last part of the ---label (--bl?)
• continue until another breakpoint is triggered (and then the current breakpoint returns to the pool).
• continue and don't stop on this label ever again.
• continue and don't stop on anything ever again.
• advance 10/X steps straight (don't stop on anything, even if a breakpoint is triggered)
• go back X levels (for example on a---b---c---d---e, and 2 levels, it will search for the first label a---b---c---[^d].* (starts with abc and continues with something other than d).

maybe use guietta instead of easygui.

[tomhea]

I continued using easygui, and I did something else.

I replaced the "skip 1000" with something much more useful - a "Read Memory" command.

You can now read memory words using the debugger.
Moreover - You can read flip jump variables, such as those used by the stl.
for example:
:h4:integer_label - This reads the value of integer_label, as if it was hex.vec 4.
You can also read bit variables, and byte variables (those are used by read_hex/write_hex).

merged in #250.