Improve Dialogs API

[njx]

The current Dialogs API is a little odd; after opening the dialog, you have to manually find the dialog DOM node by using $(".dlg-class-name.instance"), and to close the dialog manually, you have to call cancelModalDialogIfOpen("dlg-class-name"). It would be cleaner if showModalDialogUsingTemplate() returned an actual dialog object, and if that had elt() and close() methods or some such.

Also, buttons on the right-hand side have to be specified in the opposite order that you want them to appear in (right-to-left instead of left-to-right), probably because they're both floated. We should probably put them in a floated container.

[TomMalbran]

Should the returned object be a normal javascript object, or it would be better to make a new class with the methods mentioned and create a new instance for each dialog that is then returned?

[njx]

Reviewed. Will take a look at the pull request--thanks @TomMalbran.

[TomMalbran]

@njx This should be fixed now :)

[njx]

Ah, of course! Thanks again!