bind shouldn’t be scoped

[robrix]

bind shouldn’t be scoped because you should be able to interleave binds of different types:

bind framebuffer1
a

bind tex1
b

bind framebuffer2
c

bind tex2
d

implementing this now would require:

bind framebuffer1 $ do
  a

  bind tex1 $ do
    b

bind framebuffer2 $ do
  bind tex1 $ do
    c

  bind tex2 $ do
    d

which is kind of gross.