Merge pull request #56 from charlescui/master

ake ngx_mruby can read nginx build in variable and request variable.
Cosmetic changed. Replace [tab] to [space * 2] and adjust indents.
Cosmetic changed. indent space from 2 to 4.
add Nginx.redirect to serve 2 kinds redirect:
1st,serve http 3xx redirection.
2nd,serve nginx internal redirection.
Merge remote-tracking branch 'source/master'