Add Yandex Metrica Provider (http://metrika.yandex.com/).
New Provider: Evergage
Merge branch 'master' of https://github.com/segmentio/analytics.js

Conflicts:
	component.json
	lib/providers/index.js
	test/providers/index.js
	test/server/index.html
fix bug in _invoke not cloning arguments
Update Contributing.md
Update Makefile
added yandex metrica
Update Evergage integration tests to use the new format.  Also changed the negative test for ensuring the group call doesn't go through when no groupId is sent.  Now if you send an option for the first argument, it fills in the groupId with the userId instead of rejecting the call.
Update Evergage provider to adhere to the new style.
Part 1 of updating the Evergage provider to match segment.io's new formatting.  Don't ever indent things.
Some more style updating to match the new segmentIO testing styles.  Also removed a good 250 lines of test code by just doing some refactoring to centralize boilerplate code.
Remove a reference to a no longer used testing variable in the Evergage testing vars section.
Merge remote-tracking branch 'segmentio-origin/master'
release: 0.17.7

    propagating traverse isodate fix
adding a date test
customerio: added preliminary group support
mixpanel has deprecated the track_pageview method, removing it!
Merge pull request #298 from segmentio/mixpanel-pageview

mixpanel deprecated the track_pageview method, removing it!
started on new page api
Trim down Evergage provider tests in scope to be like the other tests.