Added .mailmap to clean up authors

********* PEOPLE *************
Primary reviewer: @suntzu86 

Reviewers:

********* DESCRIPTION **************
Branch Name:  sclark_382_add_mailmap
Ticket(s)/Issue(s): Closes #382

********* TESTING DONE *************

```
$ git shortlog -sne
   271  Scott Clark <scott@scottclark.io>
   267  Eric Liu <eliu@yelp.com>
   102  Deniz Oktay <denizokt@mit.edu>
    79  JiaLei Wang <jw865@tashtego.icse.cornell.edu>
    73  norases <norases@gmail.com>
     3  Peter Frazier <peter.i.frazier@gmail.com>
     1  Darwin Stoppelman <darwin@yelp.dog>
     1  Tim Joseph Dumol <tim@timdumol.com>
```

vs

```
$ git shortlog -sne
   208  Eric Liu <eliu@yelp.com>
   180  Scott Clark <scott@scottclark.io>
    96  Deniz Oktay <denizokt@mit.edu>
    87  Scott Clark <zephyr3.14@gmail.com>
    65  norases <norases@gmail.com>
    59  JiaLei Wang <jw865@tashtego.icse.cornell.edu>
    42  Eric Liu <suntzu86@gmail.com>
    17  suntzu86 <suntzu86@gmail.com>
    11  JiaLei Wang <jw865@asimov.icse.cornell.edu>
     8  Norases Vesdapunt <norases@gmail.com>
     5  bulutcocuk <denizoktay1994@gmail.com>
     4  JiaLei Wang <jw865@daggoo.icse.cornell.edu>                                                                             
     4  Scott Clark <sclark@yelp.com>                                                                                           
     4  jialei <jialei@yelp.com>                                                                                                
     3  Peter Frazier <peter.i.frazier@gmail.com>                                                                               
     1  Darwin Stoppelman <darwin@yelp.dog>                                                                                     
     1  Deniz Oktay <denizokt@140-sfoeng50-45.clients.corp.yelpcorp.com>                                                        
     1  Tim Joseph Dumol <tim@timdumol.com>                                                                                     
     1  garywang304 <garywang304@gmail.com>  
```