Embed the template text into the layer file rather than the AST.
Embed the template text into the layer file rather than the AST.

Turns out that it's problematic even to create the AST at build time, because then
(during the build) handlebars.js will create dummy custom elements (ex: <d-button>)
for introspection.  They are used to find out when to call element.foo = false
rather than element.foo = "false".

Creating the dummy elements first requires running the code to define the custom elements.
That wasn't working right during builds, because the javascript files were
referencing symbols that don't exist in Node, such as HTMLElement.

Rolls back more of (and most of) 2c0633fde5c8ef8e686b8a64209ae900ff356cba.

Fixes #438 for real, and refs #432.

Sam-Cummins/delite,Sam-Cummins/delite