0.7.0: TLS 1.3 Draft 28, 0-RTT, and cURL support

• 0.7.0 (08-14-2018)
  • TLS 1.3 draft 28
  • Client-side support for TLS 1.3 0-RTT (rustls PR #185)
  • SSL_connect and SSL_do_handshake
  • Experimental X509 and STACK APIs for Android HostnameVerifier
  • Non-blocking socket support
  • Refactored thread-local error queue, now includes error line numbers for debugging
  • catch_unwind at FFI boundaries to prevent undefined behavior
  • Link time optimization if built with nightly Rust or stable Rust >1.28
  • Curl support tested with official CI scripts and git 2.18; see the patches directory
  • cargo-fmt and cargo-clippy lint checks