Add sortable last-modified column to entry list view

[TheZ3ro]

Add sortable last-modified column to entry list view
keepassx/keepassx#192

From KeePassX Pull Request

[droidmonkey]

This is a nice solution but it doesn't solve the root problem which is not being able to customize the view in any way. This would be a great feature to bring to the app in the future.

[Thynix]

Aside from the test failure and a few minor comments that PR looks good to me.

[TheZ3ro]

Sub-issue of #17

[jab416171]

@Thynix it looks like it's just a matter of updating that one line of that one test. I can take care of that and submit a pull request against this repository with the same diff as keepassx/keepassx#192 if that's all it takes?

[Thynix]

@jab416171 I'm hardly in a position of authority here but that sounds good to me.

[jab416171]

Oh right, maybe I should be asking @TheZ3ro and @droidmonkey.

[droidmonkey]

My thoughts on this were to wait until we redo the whole display of entries. I want it to be more extensible and less hard coded then it currently​ is.

[fonic]

Covered by #849

[droidmonkey]

My mistake...