Changed constructor to handle passed in arguments

Now accepts and object, accepting a files property that functions the
same as using the use() function.
Changed end() function to handle an empty argument

Added ability to pass nothing to end(), assumes you want to generate
an, 'as long as possible' sentence.

Also changed the Internal name change of end function from fn to endFn.
Adding pickRandom function to choose words

Picks a random element from inputted list
Added function to normalize words

Instead of forcing users to accept lowercasing and stripping of all
their words.
Changed start to accept a string or function

If a string it will use that as the "starting" word,
If a function, it will get a word list passed to it and the function
can decide which starting word to use
Fixed bug with the last word not being appended
Changed sentence splitting

Converted it from only using newline to using both newline and a period
followed by a space.
Minor cleanup
Fixed tests to handle new changes