v0.20.0

• We no longer load libEGL.so and libGL.so multiple times.
• Fixes Context::is_current incorrectly returning false.
• Made ContextBuilder's pf_reqs public.
• Breaking: Renamed GlContext{,Ext} to ContextTrait{,Ext}.
• Breaking: Renamed GlWindow to WindowedContext.
• Implemented context sharing support for Windows and Linux.
• Added support for contexts made from raw parts for Windows and Linux.
• Breaking: Removed shareable_with_windowed_contexts. Now you must build
  OsMesa contexts via a separate extension.
• Added ContextBuilder::build_{windowed,headless} methods.
• Breaking: Renamed Context::new to Context::new_headless. new_headless now accepts dimensions for the off-screen surface backing it.
• Breaking: Renamed GlWindow::new to WindowedContext::new_windowed.
• On X11 and Wayland, you can now use shared contexts, however, one limitation
  of the Wayland backend is that all shared contexts must use the same events
  pool as each other.
• Added context sharing support to windows.
• Improved docs.
• Refactored code to be more consistent/cleaner. Ran rustfmt on everything.
• Added NetBSD support.
• Breaking: Removed new_shared function from Context and GlWindow, in favor of new.
• Added build method to ContextBuilder.
• Added get_egl_display method to GlContextExt trait and its implementation for platforms.
• Removed minimum supported Rust version guarantee.
• NoBackendAvailable is now Sync, as a result CreationError is also Sync.
• Update winit dependency to 0.19.0. See winit's CHANGELOG for more info.

v0.19.0

• Breaking: The entire API for headless contexts has been removed. Please instead use Context::new() when trying to make a context without a visible window. Also removed headless feature.
• Breaking: Types implementing the GlContext trait must now be sized.
• Breaking: Added new CreationErrorPair enum variant to enum CreationError.
• Remove requirement for EGL dev packages on Wayland.
• Update winit dependency to 0.18.0. See winit's CHANGELOG for more info.

v0.18.0

• cocoa and core-graphics updates.
• Breaking: Added OsError variant to ContextError.
• Improved glX error reporting.
• The iOS backend no longer fails to compile... again (added iOS testing on CI to prevent further issues).
• Update winit dependency to 0.17.0. See winit's CHANGELOG for more info.

v0.17.0

• Fix regression that prevented automatic graphics switching in MacOS (#980)
• Add ContextBuilder::with_double_buffer function
• Add ContextBuilder::with_hardware_acceleration function
• Work around a presumed Android emulator bug
  that would cause context creation to return CreationError::OpenGlVersionNotSupported
  in some configurations
  (#1036)
• Update winit dependency to 0.16.0. See winit's CHANGELOG for more info.
• The iOS backend no longer fails to compile.