Renames luajit to http lua module

with-luajit flag was being used to install the http lua module
which is slightly confusing. As luajit is the recommended env
in which to run http-lua-module i've left it as a dep. of the
module itself

What you think?
Merge pull request #6 from ninjapenguin/renames-lua-module-from-luajit

Renames luajit to http-lua-module