emulator GLESv2: fixed (#16) NenaMark crashes on exit

The GL2Encoder::m_compressedTextureFormats  member wasn't initialized, so the d'tor
would sometimes crash trying to delete it. Also init m_num_compressedTextureFormats.

Change-Id: Iae423c16a84a4e454e0e1167f7478f9e2f6183c0

tools/emulator/opengl/system/GLESv1_enc/GLEncoder.cpp

@@ -453,6 +453,7 @@ GLEncoder::GLEncoder(IOStream *stream) : gl_encoder_context_t(stream)
 {
     m_initialized = false;
     m_state = NULL;
+    m_num_compressedTextureFormats = 0;
     m_compressedTextureFormats = NULL;
     // overrides;
     m_glFlush_enc = set_glFlush(s_glFlush);