Fix be_ugly not being found on install

On `npm install grunt-behance-build`, I kept getting:

```
~/r/be.net (ugly ⚡) grunt build
>> Tasks directory "/Users/jokemp/repos/be.net/node_modules/grunt-behance-build/node_modules/grunt-be-ugly/tasks" not found.
Warning: Task "be_ugly" not found. Use --force to continue.

Aborted due to warnings.
```

Was due to filename mismatch.