Bug 1066: Reduce glGetError() in FBObject / GLFBODrawableImpl

- GLFBODrawableImpl
  - cache getMaxRenderbufferSamples() result from initialize call,
    method checks glGetError()

- FBObject
  - init(..): Remove one redundant checkPreGLError()

  - Allow reset(..) / modify-attachment-operations w/o glGetError():
    - Only check error if DEBUG || GLContext.DEBUG_GL:
      - RenderAttachment.initialize()
      - TexureAttachment.initialize()
      - syncSamplingSink(gl)
Bug 1066: Reduce glGetError() in GLDrawableHelper.reshape(.., setViewport==true)

Only check error if DEBUG || GLContext.DEBUG_GL in GLDrawableHelper.reshape(.., setViewport==true)