all adapter tests pass, rethinkdb tests added, a bunch of bugs fixed

fix "call to (*testing.T).Fatal from a non-test goroutine" in tests

remove debug printing

fixing comments

change mime-type of drafty form response

markdown tweak 3

disable "server_status": "/debug/status" by default and explain its use

zh-TW templates, improve language matching, add issing languages to c…

…onfig

bug fix in optionalHttpHeaders; deprecated ioutil removed

add HTTP headers: X-Frame-Options, Referrer-Policy