feat(uiSrefActive): Also activate for child states.

To limit activation to target state use new `ui-sref-active-eq` directive

Breaking Change: Since ui-sref-active now activates even when child states are active you may need to swap out your ui-sref-active with ui-sref-active-eq, thought typically we think devs want the auto inheritance.

Fixes #818
chore(travis): update node version
Merge pull request #927 from angular-ui/issue-818

feat(uiSrefActive): Also activate for child states.
refactor(sample): migrate sample app to 'best practice' directory layout

The current example is a bit too simplistic in my experience to fully grasp
the power of ui-router. It provides a monolithic example of state definition
that shows the varied approaches that can be used, but not in a very structured
format. This change applies the emerging best practice directory layout of an
angular application to exemplify the power of ui-router
Merge pull request #961 from mbroadst/improve-sample-structure

migrate sample app to a more 'best practice' directory layout
fix(state): allow view content loading broadcast
fix(uiSref): cancel transition if preventDefault() has been called
feat(uiSref): extend syntax for ui-sref

add possibility to pass params to current state without entering state name
Merge pull request #936 from fuzzlemuttons/patch-1

fix(state): allow view content loading broadcast
Merge pull request #966 from romario333/sref-preventdefault

fix(uiSref): cancel transition if preventDefault() has been called
Merge pull request #933 from timsly/current-ui-sref

feat(uiSref): extend syntax for ui-sref
feat($state): allow prevent syncUrl on failure

Check defaultPrevented before syncUrl on failure.
Merge pull request #967 from esion/sync_url_default_prevented

check defaultPrevented before sync url on failure
fix($state): didn't comply to inherit parameter

$state.href didn't comply to inherit parameter. Parameters aren't
inherited anymore when inherit: false (default)
Merge pull request #970 from dutchcoders/master

$state.href inherit parameter fix
refactor($state): disentangling retry logic
 - Dropping unnecessary variable assignments
 - Misc. cleanup
feat($urlRouter): abstract $location handling

 - Wrap all handling of $location and UrlMatchers and abstract away from $state
 - Expose URL-syncing interfaces
 - Refactor and simplify URL generation
chore($urlRouter): whitespace & formatting
chore($urlRouter): add tests for location syncing
refactor($state): simplify include()