Merge pull request #2 from nlfan/master

Update properties of datastream and device.
Update api doc overview
update api doc's overview for english site
Merge pull request #3 from nlfan/master

Fix bug.
update datapoint api
update api doc about data managment
fix bug about api for data managment
update response format
update links
new style of developer site
reconstruct api doc
hide en site
fix doc bugs
update keys management
new directory structure of developer site
add base
update datapoints api
update api doc about pagination
reorganize css
add blank page for blank page