Fix database icons license issues.

Pull C62_Tux.png, C63_Feather.png, C64_Apple.png, C65_Apple.png
and C65_W.png from the latest KeePass 2 version.

Replace C68_BlackBerry.png with another icon from openclipart.org.
It's unclear where this KeePass 2 icon is from.

Closes #69
Copyright format syntax fixes.
Remove wrong copyright paragraph.
Add some comments to copyright file.
Add scalable versions of the Oxygen icons.

This is required by its license. They aren't actually used by KeePassX.

Closes #70
Improve the application icon.

The one one has a shadow that looks better especially on a
dark background.

https://gitorious.org/keepassx/keepassx/merge_requests/18
Add LGPL-3 license text for the Oxygen icons.
Ignore an unused variable.
Add asserts in GroupModel::groupAboutToRemove().
Handle deleting groups more consistently.

Delete the entries and child groups in Group dtor
no what if the group has a database or not.
Stop suppressing signals in Group dtor.

That way we emit entry/group removed signals.

Move cleanupParent() call to the bottom so we
maintain the group tree structure for objects that
connect to those signals.
Add TestEntryModel::testDatabaseDelete().

It tests that EntryModel in EntryList mode correctly
removes entries from the model when that database of
these entries is deleted.
Close AutoTypeSelectDialog when there are no entries left.

This happens when the entries were deleted or the database
has been closed.
Coding style fixes.
Fix typo in filename.
Fix removal of history entries in release builds.

Closes #56
Ignore an unused variable.
Add regression test for issue #56.
Improve entry test.
Small optimizations.