BreakpointViewer doesn't reload breakpoints anymore

[pvmm]

BreakpointViewer now stores references to Breakpoints (Breakpoint, Watchpoints and Conditions) through 3 std::maps of new data structure BreakpointData because just storing references in a hidden column in QTableWidget is not flexible or powerful enough. The new data structure allows BreakpointViewer to sync with the emulator only when reconnected and not every time a new breakpoint is created or modified, which is more efficient. Also, since the table of breakpoints is not erased every time, items will not move around without the user's consent (they will not be destroyed and recreated, but reused).

minor changes:

• renamed processXXXX functions to parseXXXX because it is a less generic name;
• hidden 6th table column stores breakpoint name (id) instead of index;
• more generic and useful setTextField function instead of item->setText();
• message box displayed when error received from openMSX;
  
• the debugger now waits for openMSX response before performing changes;
• to avoid rows moving around, editing or adding a breakpoint now automatically turns sorting off.

This is an attempt to fix the remaining bugs on pull request #91.

[pvmm]

In draft mode because there are some minor glitches when changing watch points.

[pvmm]

BreakpointViewer seems to be working fine in tandem with assembly view and "Add breakpoint..." from the start.

[m9710797]

Thanks. I'll try to do a more detailed review tomorrow (or the day after).

[m9710797]

I did a 2nd pass of review. Just some minor suggestions (not required to change this).
I think it's ready to be merged. But before doing that I first wanted to ask if it's ready from your side (because I see you were still making changes).

I see you recently created PR#108, I'll try to review that tomorrow, I don't have time today anymore.

[m9710797]

Thanks a lot!