Prerender

Changed
- Set `renderType` to `html` for non "/render" endpoint

Added
- Added Headless Chrome as a rendering engine!
- Added new event types: `requestReceived`, `tabCreated`, `pageLoaded`.
- Added new Prerender server option: `chromeLocation`
- Added ability to request jpg and png screenshots
- Added ability to request pdf export of a page
- Added ability to request HAR file of page load times

Changed
- Removed PhantomJS and all references to it
- Removed old event types: `beforePhantomRequest`, `onPhantomPageCreate`, `afterPhantomRequest`, `beforeSend`
- Removed In Memory Cache (moved to new repo)
- Removed S3 HTML Cache (moved to new repo)
- Removed Prerender server options that are no longer needed: `workers`, `iterations`, `softIterations`, `cookiesEnabled`, `pageDoneCheckTimeout`, `resourceDownloadTimeout`, `jsTimeout`, `noJsExecutionTimeout`, `evaluateJavascriptCheckTimeout`

See the Readme.me for in depth descriptions of all of the new changes!

Changed
- Whoops. Make sure `shouldEncodeURLBeforeBrowserFetch` defaults to true.

Added
- Added `shouldEncodeURLBeforeBrowserFetch` to allow projects that use prerender to determine whether they want to call `encodeURI` on the URL before fetching it in PhantomJS. Useful for some URLs that might have encoded slashes in them, since encoding them further would cause incorrect behavior.

Changed
- Fixed issue where PhantomJS crashed and then disposing caused bad phantomjs state

Changed
- Bumped all dependency versions to latest