v.0.4.8

Fixes

• Add '0' to single-digit days in rfc2822 date format (@wyhaya #323)
• Correctly pad DelayedFormat (@SamokhinIlya #320)

Features

• Support wasm-unknown-unknown via wasm-bindgen (in addition to emscripten/wasm-unknown-emscripten). (finished by @evq in #331, initial work by @jjpe #287)