fix(accordion): Allow accordion heading directives as attributes.

Closes #540
fix(progressbar): user `percent` attribute instead of `value`.

Closes #535. Problem with IE10.

BREAKING CHANGE: The 'value' is replaced by 'percent'.

  Before:

  <progress value="..."></progress>

  After:

  <progress percent="..."></progress>
fix(tooltip): support of custom $interpolate.startSymbol
feat(pagination): add pager directive
feat(carousel): add option to prevent pause

sometimes we want the carousel to spin even if the mouse hovers over it. Added an option for an optional attribute, doesn't break current templates
fix(carousel): make slide 'active' binding optional
docs(carousel): add ng-docs, update demo
refactor(carousel): make optional active binding more efficient
chore(build): various fixes to the changelog task
feat(tooltip): Added mouse placement option

Adds a mouse() method to the $position service API to return the current
mouse position. The $tooltip API has been changed to allow using this
value to set the position of the tooltip element. The top left corner of
the element will be at the cursor position.
feat(tooltip): add *-append-to-body attribute

The tooltip and popover directives (through the $tooltip service) now
support using an attribute in addition to the provider to set a
particular tooltip or popover to use $body as the container for the
popup element rather than the directive element's parent.

Closes #395.
feat(tooltip): add custom trigger support

The $tooltipProvider now allows extending the default set of open and
close trigger mappings.

Closes #382.
docs(tooltip): add $tooltipProvider docs

Until now, the $tooltipProvider has been an undocumented feature, but as
there are now several options requested by the community at large, it is
finally included in the documentation.
fix(carousel): fix error with deleting multiple slides at once
fix(tooltip): make sure tooltip scope is evicted from cache

This fix makes sure the tooltip.$scope is cleared from angular.element.cache when $destroy is called, preventing a memory leak.

Closes #484
chore(build): split release process into steps
chore(release): v0.4.0
chore(release): Starting v0.5.0-SNAPSHOT
style(CHANGELOG): Fix code blocks in breaking changes
style(CHANGELOG): Highlight code blocks in breaking changes