Remove placement tutorial,
Code will move into styling tutorial
Removed alignment tutorial,
Code will be moved into styleing tutorial
renamed:    Custom Widgets.ipynb -> Date Picker Widget.ipynb
Added widget list
renamed:    Widget Styles.ipynb -> Widget Styling.ipynb
Widget styling updates for pydata2014
Updated widget events for pydata2014
Updated basics notebook for pydata2014
Added custom widget tutorial examples
Merge pull request #13 from jdfreder/notebook-docs

PyData2014 Interactive widget changes