Add env functions
Update post template
Add thread reply form
Shorten arguments with struct
Add methods on store interface
Update post interface
Add parents field and re-locate method
Implement new interface on memstore
Update parent id parameters
Add common package
Fix possible concurrency bug
Remove unused commented codes
Add initial ThreadReply code
Implement ThreadView
Add case for specialized json renderers
Add thread-reply template
Rename rend data keys
Rename board route
Add urlfor package
Update code to use urlfor