v0.5.0

• Seed updated to 0.6.0.
• [BREAKING] wasm-pack > 0.9.0 required.
• Deleted unnecessary optimize-wasm.js script.
• Minor lib.rs changes - removed Clone constraint on Msg and prerendered variable is replaced with a Model's property.
• Added wasm_bindgen_test_configure!(run_in_browser); into test.rs.
• Disabled performance hints in webpack.config.js.
• Removed critters-webpack-plugin.