Add a mailmap file (#218)

* Add a mailmap file

Isn't this:

```plain
> git summary

 project  : kraken
 repo age : 1 year, 1 month
 active   : 78 days
 commits  : 149
 files    : 816
 authors  :
    38	Patrick Christopher  25.5%
    25	Marat Garafutdinov   16.8%
    17	Alejandro Escobar    11.4%
    14	Deirdre Storck       9.4%
    10	Joe Julian           6.7%
     9	David E Watson       6.0%
     7	Yeni Capote Diaz     4.7%
     6	Aaron Crickenberger  4.0%
     5	Mark Ayers           3.4%
     5	Guinevere Saenger    3.4%
     4	Richard Edwards      2.7%
     4	Leah Peterson        2.7%
     2	Rick Sostheim        1.3%
     1	Nancy Harvey         0.7%
     1	Lee Chang            0.7%
     1	Sam Briesemeister    0.7%
```

better than this:

```plain
git summary

 project  : kraken
 repo age : 1 year, 1 month
 active   : 78 days
 commits  : 149
 files    : 817
 authors  :
    30	choused              20.1% <--
    17	Alejandro Escobar    11.4%
    17	Marat G              11.4% <--
    14	Deirdre Storck       9.4%
    10	Joe Julian           6.7%
     8	Marat Garafutdinov   5.4% <--
     8	Patrick Christopher  5.4%
     7	Yeni Capote Diaz     4.7%
     6	davidewatson         4.0% <--
     6	Aaron Crickenberger  4.0%
     5	guineveresaenger     3.4% <--
     5	Mark Ayers           3.4%
     4	leahnp               2.7% <--
     4	Richard Edwards      2.7%
     3	David E Watson       2.0% <--
     2	Rick Sostheim        1.3%
     1	Sam Briesemeister    0.7%
     1	Nancy Harvey         0.7%
     1	Lee Chang            0.7%
```
?

* Fix angle brackets for two email

.mailmap

@@ -0,0 +1,17 @@
+Aaron Crickenberger <[email protected]>
+Alejandro Escobar jaescobar.<[email protected]>
+David E Watson <[email protected]>           davidewatson
+Deirdre Storck <[email protected]>
+Joe Julian <[email protected]>
+Lee Chang <[email protected]>
+Marat Garafutdinov <[email protected]>           Marat G
+Mark Ayers <[email protected]>
+Nancy Harvey <[email protected]>
+Patrick Christopher <[email protected]>
+Richard Edwards <[email protected]>          <[email protected]>
+Rick Sostheim <[email protected]>
+Sam Briesemeister <[email protected]>
+Yeni Capote Diaz <[email protected]>
+Patrick Christopher <[email protected]>         choused
+Guinevere Saenger <[email protected]>    guineveresaenger
+Leah Peterson <[email protected]>           leahnp