Add a directives module. For now it has one directive, 'navTabs',
which automatically focuses the first input element when switching
tabs.

Expose deform as an AngularJS service so that it can be injected.
Create a deform directive which creates data bindings for forms
serialized by deform.

Markdown support

Fix #91

2. Re-added an accidentally removed line

- Open links in a new window/tab.
- Fixed some Ubuntu instructions.

Thanks @csillag

Changes made:

Until so far, the "details" and "summary" Handlebars templates referenced
the "text" field of the annotation object, and they automatically
HTML-escaped the content found there.

Since now we are placing HTML unsafe content there (the links),
this had to be changed. So now the templates are using triple-stash
(which means no automatic escaping), and reference the "rendered_text"
field of the annotation object.

This rendered_text is filled by manually escaping the text of the
annotation body, plus making the URLs clickable.

Just toying with the concept of separating h as deployed out of the
box from deploying pieces of it as a pyramid library. Separates the
application from the library by keeping application-related things
in the main module. <shrug>