mod_h2 v0.2.1

• changed apr_pool usage to have more recycling, 50% performance increase in
  loadtest
• added hack to enable mod_h2 to run in mpm_event (experimental)
• changed internal stream/data lookup from O(n/2) to O(log(n)) time
• fixed index in http2 to http1 header conversion leading to segfaults
• update openssl version downloaded for sandbox
• using sha256 for self-signed sandbox certificates
• sandbox certificate no longer announces itself as roo
  (last 3 thanks to michael.koeller at greenbytes.de)