Merge branch 'feature-admin-ui' into feature-admin
admin: Fix actions on user index page

Make actions work for multiple users.
admin: Refactor actions to accept functions

Add to the action class an ```f``` field, which can be used to store the
associated function with this action.
admin: Add actions for VMs
admin: Add allowed operation list for VMs
admin: Add actions for projects
Merge branch 'feature-admin-actions' into feature-admin

Fixes #25
admin: Uncomment VM actions temporarily
Merge branch 'feature-admin-vm-details-fix' into feature-admin
admin-ui: Fix style of sidebar
admin-ui: General improvements on css, js, html
admin-ui: Add demo of pie-chart with Highcharts plugin