Merge pull request #38 from caiiiycuk/master

Add note about keepalive connections in nginx
"page cache" vs "action cache"
Fix #39 Rename terms: upstream -> inbound, downstream -> outbound
Fix #41 Cookie: setMaxAge(Integer.MIN_VALUE) -> setMaxAge(Long.MinValue)
Update deps.png for Xitrum 3.3
Update howto example for FileMonitor
Fix #42 3.4: Fix guide about setting language
Improve Guide
Removed typo in websocket (async.rst)
Merge pull request #43 from themerius/master

Remove typo at async.rst about WebSocket
#43 Use ScalaRunTime.stringOf to visualize bytes
Corrected JSON code (js.rst)
Merge pull request #44 from themerius/master

Correct JSON example at js.rst
Update deps.png for Xitrum 3.5
#45 Add guide for metrics
Improve doc about metrics
Fix #46 Update "how to modify routes"
Update deps.png
3.6 deps.png
Improve architecture diagram