Add an "Edit Mode" to Dashboard view

[mistercrunch]

What changes when toggling between edit/view mode:

• can't edit title
• can't remove slices
• can't move slices
• only actions available: "force refresh" and "set autorefresh"

[graceguo-supercat]

Hi Max, thanks for adding 'Edit Mode'. I have a question, please see the attached example:
User has a dashboard with a filter-box, which can apply filter to all slices. If they changed filter, they can also saveas/overwrite the dashboard with changed filter value.
So In this use case, applying filter and save dashboard with different filter value, is it to be in a edit mode?

[mistercrunch]

Right, we need to allow for "Save As" in view mode. I had missed that. Let me add it back.

Note that changing the filter does not trigger the "has changed" notification.

[mistercrunch]

@graceguo-supercat I addressed your comment

[graceguo-supercat]

@mistercrunch It looks good to me. Only 1 question to clarify: all of the components' editMode default value is false, but dashboard's initial state is set editMode be true. is it an intended design? thank you.

[mistercrunch]

@graceguo-supercat good point, I meant to set editMode's default to false everywehre, let me fix that.

[graceguo-supercat]

LGTM