Add a "Downloading..." dialog with progress bar and cancel button for all download activities

[GoogleCodeExporter]

This issue applies to downloading new generators and functions, as well as 
graphs downloaded from the online repository.

Presently, no dialog is issued whilst downloading files from the web.  As a 
natural consequence the user is given no indication of progress, nor any 
ability to cancel (in the event of mistaken download or a particularly slow 
connection).

Additionally, this issue will require centralization of all download functions 
(away from DownloadDialog and OpenFromTheWebDialog).  This, however, is a 
necessary step towards allowing functions and generators to be loaded into 
VisiGraph without requiring a restart.

As I see it, the pattern should be passing the urls to the showDialog function, 
which then returns a hashmap matching urls to their download statuses (e.g. 
success, fail, canceled).  This way VisiGraph won't try to open files not 
properly downloaded / canceled.

Original issue reported on code.google.com by 0x24a53...@gmail.com on 16 Jun 2011 at 5:42

• Blocking: #115

[GoogleCodeExporter]

Original comment by 0x24a53...@gmail.com on 16 Jun 2011 at 5:47

[GoogleCodeExporter]

Refactored download behavior out to a new DownloaderDialog class utilizing a 
SwingWorker and ProgressMonitor.

Original comment by 0x24a53...@gmail.com on 1 Jul 2011 at 7:28

• Changed state: Fixed