WINTERMUTE: Handle a few more error conditions.
WINTERMUTE: Fix behavior of RemoveBreakpoint
WINTERMUTE: Add getTypeStr() to ScValue

Useful for error messages in debugger.
WINTERMUTE: Handle WRONG_TYPE in getErrorDisplayStr()
WINTERMUTE: Fix handling of no source case in getSurroundingLines
WINTERMUTE: Fix formatting of error message, case IS_BLANK
WINTERMUTE: Correctly handle SOURCE_PATH_NOT_SET case in printSource()