use mrb_str_new_lit instead mrb_str_new_cstr

It is a little efficient.
Merge pull request #84 from cubicdaiya/feature/mrb_str_new_lit

use mrb_str_new_lit instead mrb_str_new_cstr
Update mruby
replace RSTRING_PTR with mrb_str_to_cstr for null-terminated
Fix bug: use mrb incrrectly
Add directive, filter_handler and handler code into module code
Add state code into module code
move core function for module function into module.c
remove raise error for file
build fail mrbgems commented out for now.
remove unneeded prototype declare
change init function decraration point
Add extern flag to some functions
cosmetic change for some indents
Fix typos and minor rephase
Merge pull request #85 from Zorbash/patch-1

Fix typos and minor rephase
Add Nginx::Server#{path,realpath_root}
changed "Nginx" module to class
Merge branch 'master' of github.com:matsumoto-r/ngx_mruby
Add Nginx.echo