[PROPOSAL] [4.2] Blade 2.0 [TAKE 2]

This is the fast speed improvements to the blade compiler by @dyatlov in #2952 with the correct laravel coding standards. I hoped this could be reviewed again by @taylorotwell. It would be such a shame to throw away @dyatlov's good work. Also, now that I have fixed the tabs/spaces issue in the original pull, the diff is easier to read.