Update VE core submodule to master (673cf05)

New changes:
6cfcc85 Set ready delay to animation duration in VE WindowManager
fd9219c Refactor WindowAction to include close and toggle methods
5b175bb Update PapaParse to 4.0.6
21754e2 Move toolbar scroll hack to surface
68499c9 Switch to personal fork of Papa Parse
3d60460 Allow empty IME test suite

Local changes:
* Comment out the last remaining IME test, because it broke in PhantomJS

Change-Id: Idac659323b3e612a77b03f449dc8c89618e00f87