dillon1000/react

Infer more primitive types

Handles three more cases: 

* Template literals 

* deletion (property/computed) 

* type casts 

Only the latter has an observable impact, though i added tests for deletion just 
in case and found a bug. For type casts, they're reasonably common internally 
for fixmes, so this PR will help to ensure we don't drop type information just 
because of a cast.