rebar.config in exodm references master branch of Exometer

ERL: R15B02
Exodm: 1.3.rc5

The rebar.config file in exodm references master in Exometer.  I believe the following needs to be changed if one want to build the 1.3 release?

```
, {exometer, ".*", {git, "git@github.com:Feuerlabs/exometer.git",
              {branch, "master"}}}
```

to 

```
, {exometer, ".*", {git, "git@github.com:Feuerlabs/exometer.git",
              {tag,"1.1"}}}
```
