dillon1000/react

Two more fixes for document.createElement mode

Is this all of them? I hope so.

- Set text content after creating hierarchy, like the text is a child. I should've done this originally but I guessed it wouldn't matter. I was wrong (~20% perf difference in IE11).
- IE throws when setting an enum-like property to an invalid value. I tried setting every property to the string 'a' and changed the ones that threw to be MUST_USE_ATTRIBUTE. I think these are all correct -- encType is the most suspicious one based on the existing comments but I tested in IE8 and it works fine as an attribute.