Merge pull request #65 from DraganMileski/master

Introducing the Alert widget with a Sensu datasource
simplified widget plugin code/docs
adding missing semicolon
preliminary http proxy support for graph widget
add jquery pass through angular-ui plugin
only update if size changed
widget show template
more detailed comment
fix contenteditable
ensure browser page reload doesn't break widget layouts #66
fix initial widget positioning again
only recalculate graph size_x if changed
fix selectable list
remove stacked graph option, not supported by flotr2

* will be back when using rickshaw.js again
set graph_type correctly