WIP add ispy-online to bower.json

You can keep the "canonical" version here and just install your version locally using:
```console
$ pip install -e git+https://github.com/tpmccauley/invenio-previewer-ispy.git#egg=invenio-previewer-ispy
```
and when you are done, just create a pull request to `inveniosoftware/invenio-previewer-ispy`.