UGENE auto-update: new UGENE versions and external tools

Description: A user now requires to re-download UGENE each time new version is come out. The packages can be very big, especially the NGS packages. Also, the external tools can now be installed only manually, i.e. manually downloaded from the UGENE web site. This feature will allow to automate all this processes and, therefore, to save time of the users. It will also make their work with UGENE more efficient as they will use the latest UGENE version with all the updates and bug-fixes.
Scope:
1) Allow a user to select one of the following:
Always update UGENE automatically
Ask a user when a new version is available
Do not update UGENE automatically
2) Provide a way to automatically load an external tool from the UGENE web site if it is required. For example, if a user wants to use TopHat, but there is no such tool installed, the user should be asked, if he/she would like to install it automatically.
Also, provide a way to install the tools automatically from the External Tools tab of the UGENE Application Settings.