Added option to use make option SSL=none to compile without support for SSL and no linking of OpenSSL.
Added line explaining compilation without SSL support.
Added installation pointers in docs.
Provide helpful error message when user is trying to use SSL without have the option set in the TURBO_SSL global.
Always load crypto.lua, what to return is decided by this module.
Merge pull request #96 from kernelsauce/ssl-option

Made it simpler to run Turbo without any SSL support.