New method just for parsing the loose arguments
that can be passed to the "respond()" method and its aliases
Changing over all of the respond aliases to use
the variable "path" instead of "route" to stay consistent
and to be compatible with parsing the loose arguments via the new method
Now separated/abstracted the path string processing
out from the `respond` method and into its own method

Further explained the `respond` method
New aliases for OPTIONS and HEAD.
Bitches love aliases.
[https://github.com/chriso/klein.php/commit/e8357bf0cee31089fd466101aecb7dc803b964a4#commitcomment-2820393]
Making the message make more logical sense for the
Route class' InvalidArgumentException
New abstract class for a factory for building Route instances
Abstracting out the route building and pre-processing
into its own factory class, which will allow others to implement their
own Routes and Route building process
Refactoring the Klein respond method by abstracting
out the build process of Route instances