chore(ngdocs): disable lunr search during e2e tests

lunr has been responsible for slowdown in our test suite by adding ~1sec per
end-to-end test.

(this is because it initializes the index when the app starts)

since out test suite primarily tests the examples, it's reasonable do disable
the search as a temporary meansure.

the real fix is to use protractor and extract all of the examples into
standalone apps which can be tested without bootstrapping the whole docs app.
chore(ngdocs): disable code prettification in e2e tests

code prettification is expensive and not needed for e2e tests, so I'm disabling
it to speed up the e2e test suite.

this is a temporary measure, see previous commit for more info.
chore(ngdocs): disable google analytics in e2e tests

GA is not needed during e2e tests, so I'm removing it to speed up the e2e test
suite.

See previous commits for more info.
fix($injector): don't parse fns with no args

When annotating a fn, it is wasteful to try to parse a fn that has no arguments
as such fn has no injectable dependencies