Added prepare and serve functions.

Added glazyPrepare functions, for preparing elements and lines of
content joined by whatever you choose. Convenience functions added for
line breaks, raw HTML, and joining with no space.
Display prepared elements using the glazyServe functions.

Refactored internal open elements and attributes buffer code.
Rewrote glazyElement to use new prepare/serve functions.

Removed glazyMultiple functions which are replaced by easier to
understand and more flexible glazyPrepare functions
Remove some old deprecated functions.