Simplify respacing SupSub next to \int's #simplify
Fix respacing PlusMinus

If there's lost in a row, like 1++++2, they should all be unary
operators on the 2 except for the first, like, 1 + +++2, not only the
rightmost one being a binary operator. Also, the binary operator to the
left will have padding, so no reason to have padding on a unary
operator.
Fix spacing unitalicized operators next to numbers
Fix typo in visual test case #test #typo
Merge pull request #255 from mathquill/fix.respacing

Fix spacing of SupSub, PlusMinus, unitalicized operators