Select unit test: fix malformed HTML (although harmless)
put back attachedCallback call and remove upgrade call.

The reason is upgrade is anyway call when I instanciate the
custom element instance automatically but then as the element
is not attached attachedCallback is not called. Calling upgrade
later is then ignored and attachedCallback still not called.
So one as to just call attachedCallback.
Update index.md

Add ResponsiveColumns to the list of widgets
created sample for ToggleButton and added it to docs/ToggleButton.md
fixes in Select functional tests
Use the current page URL's protocol to access the Flickr API, to avoid request failures when the app is launched using https://
From https://github.com/ibm-js/deliteful-tutorial/pull/2
Thanks  @modcoms  (Martin McCormack)
let's do an alpha.2
Add a sample that reproduce #270
Update to match new code generated by generator-deliteful-app using <d-store> element instead of <d-list-store>.
Assign a store to the d-select element as it does not have one any more after recent deliteful changes (d-store element).
Assign a store to the d-select element as it does not have one any more after recent deliteful changes (d-store element).
Fix duplicate line in previous commit.
Minor updates to deliteful docs, mostly grammar related changes.
ComboBox widget: initial implementation
ComboBox: added screenshots for user doc
ComboBox: fix in template
Clear the left menu pane in part 4, so it does not throw errors when user clicks the menu items.
Minor updates to deliteful/List docs.
New screen shots for part 6.
Add link to live demo for part8-1.