Fix taint analysis of binary operations

Use forked collections for now

Use fork for now

Add slash

Only care about high for now

Fix vimeo#2380 - prevent string docblock for callable param

Fix vimeo#2348 - ensure all functions and methods return some type

Fix more try/catch stuff

Fix vimeo#2309 - prevent closure-inferred generic template params ove…

…rwriting parent ones

Fix strtolower ref