API change for functions that take some "specification" as argument.

[Noeda]

For example, newBuffer, newTexture, runDraws and draw all take a record value that have many fields, some are set, some or not. Now that we depend on lens, we could do something like this:

-- Old API:
-- newBuffer :: MonadIO m => BufferCreation -> m Buffer
newBuffer defaultBufferCreation { bufferSize = 123, initialData = Just some_ptr }

-- New API:
-- newBuffer2 :: MonadIO m => (BufferCreation -> BufferCreation) -> m Buffer
newBuffer2 $ (bufferSizeL .~ 123) . (initialDataL .~ Just some_ptr)

Some of the new convenience functions I wrote for Graphics.Caramia.Buffer already use this. The default value is supplied by the function itself; user changes fields they want. And lens is excellent at this kind of use.

TODO: Add lenses for all the specification records and export them. Add new API functions.