Free each _floatBuffer array individually.
Fix retain cycle where the EZAudioPlotGL retained EZAudio's GLKViewController, even though the view controller retained the EZAudioPlotGL (the view)
Remove some redundant code.
2 issues: 1) glPush and glPop have been removed from OpenGL ES 2.0 are no-ops that cause GLWarnings (in xcode, you can break on any glerror). 2) baseEffect prepareToDraw needs to be set after setting the effect's transform matrix. Otherwise the transform matrix doesn't take effect until the next frame. When animated mirrored plots, this resulted in the mirrored drawArray being off by a frame.