Rename Templatizer->Templatize & add bc Templatizer behavior

[kevinpschaaf]

Rename Polymer.Templatizer library to Polymer.Templatize & add pseudo-backwards-compatible Polymer.Templatizer behavior for slightly better hybrid support.

For now, users will need to implement both 1.0 & 2.0 callbacks differently (to e.g. deal with path differences due to removal of Collection, different TemplateInstance API, etc:

Example hybrid element:

Polymer({
  ...
  behaviors: [ Polymer.Templatizer ],
  // 2.0 callback implementation
  _forwardHostPropV2: function(prop, value) { /* use 2.0 API */ },
  _notifyInstancePropV2: function(inst, prop, value) { /* use 2.0 API */ },
  // 1.0 callback implementation
  _forwardInstancePath function(inst, path, value) { /* use 1.0 API */ },
  _forwardInstanceProp function(inst, prop, value) { /* use 1.0 API */ },
  _forwardParentPath: function(path, value) { /* use 1.0 API */ },
  _forwardParentProp: function(prop, value) { /* use 1.0 API */ },
  ...
});

[web-padawan]

@kevinpschaaf could you check these issues please?
#3755 #3307

[blasten]

I changed _ctor toctor since that is how it was defined in v1.

[blasten]

Having the tests (Templatizer related) for iron-list 2.0 in hybrid mode passing, I think the changes LGTM. Thanks!

There are a few remaining issues we can address on separate PRs if necessary:

1. selectIndex/deselectIndex in array-selector for v1.
2. Debouncer now has a flush method, but it used to be called complete in v1. It could possibly be fixed in Introduce new API for debouncer and Async #4182
3. A story around making Introduce new API for debouncer and Async #4182 v1-compatible.

[sorvell]

LGTM

[kevinpschaaf]

@blasten We treated this PR as an overall review of the 2.0 Templatizer API, and made the following changes:

• Renamed callback fwdHostPropToInstance -> forwardHostProp
• Renamed callback fwdInstancePropToHost -> notifyInstanceProp
• Renamed behavior callback _fwdHostPropToInstance -> _forwardHostPropV2
• Renamed behavior callback _fwdInstancePropToHost -> _notifyInstancePropV2
• templatize now takes 2nd arg for the binding context of the callbacks (normally this of the element calling templatize)
• removed first argument of forwardHostProp callback, since the function is bound to the 2nd arg of templatize, which is what you want
• TemplateInstance constructor no longer takes host argument
• TemplateInstance API forwardProperty & flushProperties removed
• TemplateInstance API forwardHostProp added, should be called from forwardHostProp callback

Refer to e.g. dom-repeat implementation for usage changes...