v0.4 Release

Changelogs:

• #15 exposed keepalive and max header bytes size server properties
• #10 onafterreply server extension point added and decorated methods seturl and setmethod added to context
• #13 cookie method added to reply builder and test case update
• #16 added gzip response with configurable level
• #19 expanding possibilities - handler, handlerfunc to aah middleware
• #21 unique request id implemented
• #17 pool size value made configurable
• #23 onshutdown event added
• #23 listening signals, go1.8 grace shutdown and publish shutdown event
• #20 session and session store is done
• #25 view library is extensible
• #29 migrated session lib into security lib
• Code improvements