feat(typeahead): add typeahead directive

Closes #114
feat(accordion): enable HTML in accordion headings

Defines a new directive <accordion-heading> that can be used below <accordion-group> elements to provide HTML to be transcluded into the group's heading.
The transcluded headfng is compiled and linked to the same scope as the transcluded body - so it can contain AngularJS directives itself.
fix(accordion): fix minification issues
chore(*): update angular to 1.0.5 and bootstrap to 2.3.1

Closes #178