Added file uploading and welcome screen for creation of initial entities

Add plupload

- Dataview creates plupload instance
- Navigator panel views act as drop zones

Improve drag and drop file upload

Added welcome guide to create first project, experiment, epoch group, and epoch

Limit drag n drop file upload to epochs and measurement panels
Merge pull request #14 from kvedananda/dev

Added file uploading and welcome screen for creation of initial entities