Remove needless interface and resolve some minor mistakes.

REM AMF0SimpleEncoder interface because it served little purpose.
MOD AMF0SimpleOutputStream to be standalone without implementing the removed interface.
MOD Rename some verbose methods in AMF0EncodingBuilder.
FIX Typos related to escaping quotes in AMF0EncodingBuilderNGTest.
MOD Multiple files to remove no longer useful imports that were overlooked previously.