red-brick/pw: Make Java main class search abortable
red-brick/pw: Report data from Java main classes script in the final format
red-brick/pw: Improve Java class path handling

Instead of using absolute paths for automatically added class path
entries, use paths relative to the bin directory. But internal
convert them to absolute path before passing them to the JVM, so
they are independent from the current working diretory.

Also replace the menu-based Add button with a dialog-based one. This
has better usability, supports auto-completion and free-form input.
red-brick/pw: Add Java summary
red-brick: Add missing format string parameter to several error messages
red-brick: Handle IP Connection level errors in all places that handle RED errors
flashing: Add missing initialization of refresh_updates_pending
Remove trailing whitespace from plugin __init__ files
More whitespace cleanup
Remove unused imports
Remove semicolons
Fix incomplete __init__ functions

Found by pylint.
Remove unused code
Prefer new-style classes
red-brick: Move return statement to correct place in ScriptManager
Fixx usage of undefined variables
red-brick: Add missing QMessageBox imports
red-brick: Avoid redefining Python keywords
red-brick: Fix indentation