Remove the name `urth` from all our elements and apis

[lbustelo]

The goal of this issue is to get rid of the urth name from anything that is accessible by the end user. A couple of items include

• [ ] Rename all elements to change <urth-core-*> or <urth.viz.*> to <jupyter-*>. For example: <urth-core-function> -> <jupyter-function>
• [x] Rename urth.widgets.* to jupyter_declwidgets.* (open for suggestions) in python and scala
• [ ] Deprecate the UrthData and Urth globals
• [ ] Rename urth_components directory used in the link tag href

[lbustelo]

Refs #141

[parente]

Rename urth.widgets.* to jupyter_declwidgets.* (open for suggestions) in python and scala

Just curious, would it be possible to still alias jupyter_declwidgets with urth.widgets just so that all the notebooks in existence continue to work? We don't necessarily have to because it's all < 1.0 and incubator, but would be nice if it's not a huge pain to maintain such an alias.

[lbustelo]

Not sure if that is possible, but I we would certainly look into it.

As a note, we should do the same for the Python and scala libraries.

[lbustelo]

Some work for this is being done in #315

[lbustelo]

The rename of the kernel APIs is being done in #389

[parente]

Is urth_components going to change too?

[lbustelo]

It probably should... to what?

[aluu317]

After talking to @lbustelo yesterday, he suggested that we find a way to make the transition from urth-* to jupyter-* by first supporting both namings so it's backwards compatible for the current demo/example notebooks.

I was hoping we could do this by using Polymer inheritance support. Unfortunately, Polymer 1.0 only supports extending native html elements, as opposed to extending custom elements (looks like they're working on it for future release): https://www.polymer-project.org/1.0/docs/devguide/registering-elements#type-extension

[lbustelo]

Removing this from the milestone. Renaming the elements at this point does not buy us anything other than more pain. There is no easy way of doing it other than copy/paste.

[haobibo]

How about create two folders in elements: jupyter-core and jupyter-viz? We can keep the urth-* and make them depreciated in this version (0.x.x), and abandon them in next major version (say 1.x.x).

The current organization of the urth- components are in a flat style, I wonder if we can we put all urth-core-* into jupyter-core, and put all urth-viz-* into jupyter-viz, because visualizations like line, pie, bar, etc. are quite similar to each other and use the same library (nvd3). Typically, users may want to develop some other viz elements using third party JS libraries like highcharts, eCharts, etc. For each library, it supports many types of charts. I wonder if it's better to put such similar components into same folder.

[lbustelo]

@haobibo So the main headache was that we could not find a way to create aliases in Polymer without basically having to copy code.