Commit 56 (Beta Candidate)

IMPORTANT: This commit corrects an important IE8 bug that was
in the previous commit (55)

This commit also includes some significant updates and improvements:

- New API for creating derived tags - simply specify "baseTag" on
  the custom tag declaration:

  $.views.tags({
    range: {
      // Inherit from {{for}} tag
      baseTag: $.views.tags["for"],
      ...

  See samples: http://www.jsviews.com/#samples/jsr/tags/extend-for
  and http://www.jsviews.com/#samples/tag-controls/range

- trigger=true on data-linked inputs, or two-way binding now uses
  keydown - so data entry updates as you enter each key.

  Setting trigger=true on data-linked inputs, textareas, content-editable
  elements, or custom tags such as {{textbox}} (with two-way binding
  through linkedElem) now triggers immediately after keydown, rather
  than on keyup as previously.
  So setting <input data-link="name trigger=true" />. for example,
  means the name property will update as you enter each character.

- Improvements to DataMap feature. Used for {{props}} tag.
  Examples to follow.

- Support for loading JsObservable (jquery.obserable.js) without JsRender
  for observable-data scenarios without JsViews.

- Support for flexible load sequence for JsViews: Can now load
  JsObservable before JsRender and JsViews, as well as the more
  normal sequence of JsRender, JsObservable, JsViews (as used in the
  single file jsviews.js).

- Many new unit tests for JsObservable.

- {on now supports passing parameters directly to the bound method:
  e.g. {on ... method param1 param2}
  Examples to follow.

- Improvements to contentEditable support.
  Examples to follow.

- Use of autoBind property on custom tags no longer necessary.

- Bug fixes:
  https://github.com/BorisMoore/jsviews/issues/264
  https://github.com/BorisMoore/jsviews/issues/265
  https://github.com/BorisMoore/jsrender/issues/238
  https://github.com/BorisMoore/jsviews/issues/267