Updated formulae for digikam and marble. Based on #9

[strank]

Updated urls and sha1s, added exiv2 as dependency for digikam.

For me, marble produces a conflict with shared-mime-info and it doesn't link the FindMarble.cmake file as it should. No idea how to address those.

DigiKam seems to work, except for the table view.

[strank]

One more update: the crash when selecting tableview only occurs when the "widget style" preference in the miscellaneous settings is unset, which it was for me by default. Setting any of the styles there (from windows to plastique or aqua) prevents the crash, and digikam works without issue so far.

[strank]

One more reproducible crash encountered: Opening the import dialog (import files, or import from camera) fails with a crash in Digikam::DCategorizedView::updateDelegateSizes. Couldn't find a reason for that yet.

Otherwise working fine.

[adymo]

@strank do you use Digikam on Mac?

[strank]

@adymo yes, I did, working around the crashes I mentioned. Haven't used for quite some time now, but it's still installed.