fixes #209

closes #201

fixes #202

With this commit the icons from FontAwesome are used. To achive this the
webpack css-loader is used and the location for the module.css has slightly
changed.
Also I removed the ugly sidebar (what a short life) and added a slim navbar at
the top for the detail views.

This adds a new FilteringNotifier which can use filters to suppres certain
events from being notified of. Two filter implementation are provided, one
filtering by name and one by id. Additional when a FilteringNotifier bean is
present, the autoconfiguration creates a REST-controller to add and remove
filters at runtime.

 - Updated Angular to 1.5.3
 - Removed Angular UI Bootstrap, to make the Angular update possible without
   updating Bootstrap
 - Moved every view into its own module
 - Added concatenation of the module js and css assets to the webserver
 - Created directives/components for the various visual components and trimmed
   down the controllers
 - Removed unecessary ngRoute
 - Removed classpath section in details (it is included in environment)
 - Moved the counters and gauges to a separated metrics view
 - Added target="_blank" for the logfile
 - Added information about version, loaded ui modules to the about page
 - Extracted the activiti view to a separate maven artifact

With this commit it is now possible to add your own ui modules to the servers
classpath and they will show up in the ui.
Every module needs an "entry" script file in the classpath located under
`META-INF/spring-boot-admin-server-ui/<modulename>/module.js`.
The module is be implemented as angular module and needs to be added to
the global `uiModules` list.
The spring-boot-admin-server-ui-activiti module is a simple sample for
adding a application view but it is also possible to add main-views.
Please have a look at the events module in spring-boot-admin-server-ui/modules.

Please note that the internals of the ui can change anytime.

From Spring Cloud Brixton on, the PreDecorationFilter doesn't pass sensitive
headers downstream.
So the ZuulProperties from the ApplicationContext needs to be used (instead
of creating a new instance), so that the properties can be customized.

Update to Spring Cloud Brixton and add the concept of ServiceInstanceConverters.
A ServiceConverter is used to convert discovered ServiceInstances to
Applications. The old converter and one for Eureka is provided. It is also
possible to provide your own implementation.

closes #154

fixes #184

fixes #175

added CompositeNotifier to allow for multiple notifiers. Only used when multiple notifiers are configured and no primary notifier is already configured.

Chrome dosesn't send parallel requests for the same url. To circumvent that
behavior add a dummy request-parameter to the event-stream url. Otherwise
the journal section shows no content on chrome while doing the sse long polling

Fixed HipchatNotifierConfiguration to be a static class

changed HipchatNotifierConfiguration to be a static class, otherwise application context doesn't start up when hipchat notification is enabled.