Editor: remember breakpoints in workspace state

[ivan-mogilko]

Suggestion is to serialize breakpoint positions in the project script, and restore them when opening a project once again.

When testing certain case, or debugging some problem, sometimes we have to restart the project, or open it later, and it would be convenient to have breakpoints restored automatically, instead of setting them in all places again.

There may be a new option in preferences which toggles this behavior, like "Restore breakpoints when opening a project".

Breakpoint position is made of script name and line number.
The list of breakpoints could be serialized by ScriptsComponent class, by implementing IPersistUserData interface and its methods (that will correspond to saving and reading a chunk in Game.agf.user file).
(See how DebugLogComponent is doing this, for example)