Add driver.resource stub.
Merge branch 'develop' into topic/rewrite_phantomjs
driver.resource: Stub in start(), end(), error()

[ci skip]
Split off PhantomJSCoprocessor
STASH
coprocessor: Fix html/pdf snapshot logic
WIP Rewrite phantomjs script with Haxe version with RPC polling
WIP Rewrite PhantomJSRemote to PhantomJSDriver
driver: WIP Rewrite PhantomJSClient into PhantomJSPool
driver: Fix up phantomjs pool unit tests
driver: WIP Add resource unit tests
driver: Clean up a bit and add get_page_url(), resource_timeout
driver: WIP add scroller module.
Merge branch 'develop' into topic/rewrite_phantomjs_2

Conflicts:
	wpull/processor/web.py
travis.yml: Blacklist topic/rewrite_phantomjs_2
driver.process: Wrap try-except and log on error reading stdout/stderr
WIP coprocessor.phantomjs rewrite.
Fix up phantomjs events and resource tracker events
driver.phantomjs: Fix process reuse
coprocessor.phantomjs: Fix up url rewriting hacks. Clean temp files.