feat(bower): add bower.json

Now you can publish `delta-pouch` in bower by simply doing:

```
bower register delta-pouch https://github.com/redgeoff/delta-pouch.git
```

Then whatever tags you create will upload that version to bower. So your workflow for a release will become (assuming you have done `npm install -g tin`):

```
tin -v 1.0.7 # modifies both package.json and bower.json
npm run build
git add -A
git commit -m '1.0.7'
git tag v1.0.7
git push origin master --tags
npm publish
``` 

Looking forward to having delta-pouch in bower!  :)