Adding progress dialog class.  Built in wx.ProgressDialog isn't
suitable because its Cancel/Abort functionality is not reliable,
and it is modal, which would disable hiding/showing of the debug window.
Move the new version alert dialog code into its own module.
Merge branch 'master' of https://github.com/CVL-dev/cvl-fabric-launcher
A progress dialog class which is non-modal (so we can still show/hide
the debug window.)
- Moved logger definitions to before version number check, because if the
    version number check fails, logger_debug will be called.
- Moved new version alert dialog into its own module.
- Created a custom progress dialog, and implemented it in the login thread.
Merge branch 'master' of https://github.com/CVL-dev/cvl-fabric-launcher