Rename redundant wording EGL.eglErrorCode to just EGL.errorCode.
Add concepts of current context, and current draw and read surfaces on that context. Implement functions eglGetCurrentSurface(), eglGetCurrentDisplay() and eglGetCurrentContext(). Allow passing EGL_NO_SURFACE and EGL_NO_CONTEXT to eglMakeCurrent. Fixes #1793 and #1775.
Add unit test for EGL context creation and confirming that #1775 and #1793 work.
Merge pull request #1797 from juj/egl_context_state

Egl context state