Authentication

Branch: Authentication
Feature: Service API can only be accessed by a valid token which is generated by verifying the credentials.
Functions, and files which does the same are added.
I twould be much cleaner if you simply did:
it =  argvals.find("username") ;
it2 = argvals.find("password");
if( it != argvals.end() && i2 != argvals.end()){
...
}
Easier to understand

And it would be much more efficient, if you created your own function which iterated over argvals looking for username password.