readme: fixes typo
readability: improves variable declaration
refactoring: follows expressJS best practice
server: ensures we are not listening on the public interface
readme: gives credit where credit is due
Revert "server: ensures we are not listening on the public interface"

This reverts commit 272b9fdec7eadfa83ec57b7563788611ecdc5534.
config: specifies a nodeJS version
readme: updates server name on heroku
refactoring: simplifies code
refactoring: simplifies code
server: messages when ready
cleaning: removes useless white space
optimization: loads serialized sequences file on server init
refactoring: simplifies serialized sequences loading logic
algorithm: forces letters to be lower cased
refactoring: uses lodash to retrieve an array with unique values