refactor(perf): use webdriver to execute benchmarks

- use performance log of chromedriver / appium to get timeline data
  for calculating metrics for benchmarks
- change all benchmarks to be made of a standalone application
  and a protractor test that collectes timeline data
- fix and simplify benchmarks
- add dart2js to build
- remove benchpress

Closes #330

scripts/travis/build.sh

@@ -1,5 +1,4 @@
 #!/bin/bash
-
 set -e
 
 echo =============================================================================
@@ -17,4 +16,18 @@ pub install
         --browsers=$BROWSERS --single-run
 ./node_modules/karma/bin/karma start karma-dart.conf \
         --reporters=dots \
-        --browsers=$BROWSERS --single-run
+        --browsers=$BROWSERS --single-run
+
+./node_modules/.bin/webdriver-manager update
+
+function killServer () {
+  kill $serverPid
+}
+
+./node_modules/.bin/gulp serve.js.prod serve.js.dart2js&
+serverPid=$!
+
+trap killServer EXIT
+
+./node_modules/.bin/protractor protractor-perf-js.conf.js
+./node_modules/.bin/protractor protractor-perf-dart2js.conf.js