refactor(benchpress): export webdriver adapters in benchpress/benchpress

Also adds default bindings for protractor.
Also removes sync web driver adapter for Dart as we don’t have tests
for it yet.

modules/benchpress/common.js

@@ -0,0 +1,20 @@
+export { Sampler, SampleState } from './src/sampler';
+export { Metric } from './src/metric';
+export { Validator } from './src/validator';
+export { Reporter } from './src/reporter';
+export { WebDriverExtension } from './src/web_driver_extension';
+export { WebDriverAdapter } from './src/web_driver_adapter';
+export { SizeValidator } from './src/validator/size_validator';
+export { RegressionSlopeValidator } from './src/validator/regression_slope_validator';
+export { ConsoleReporter } from './src/reporter/console_reporter';
+export { SampleDescription } from './src/sample_description';
+export { PerflogMetric } from './src/metric/perflog_metric';
+export { ChromeDriverExtension } from './src/webdriver/chrome_driver_extension';
+export { IOsDriverExtension } from './src/webdriver/ios_driver_extension';
+export { Runner } from './src/runner';
+export { Options } from './src/sample_options';
+export { MeasureValues } from './src/measure_values';
+export { MultiMetric } from './src/metric/multi_metric';
+export { MultiReporter } from './src/reporter/multi_reporter';
+
+export { bind, Injector, OpaqueToken } from 'angular2/di';