Register servlet context listener

* GuiceFilter will handle all requests
* Bindings are configurable in 'GezzyServletModule'
Route all requests through 'GuiceContainer'
Create examples

The examples show how to bind a jersey ressource and a servlet.

Both of them can take advantage of Guice's Dependency Injection.

Note that the HelloMessageService is bound in 'RequestScope', thus
a 'Provider' needs to be injected. The concrete 'HelloMessageService' can
be obtained 'during' a request, for example in the servlets 'service()'
method.

Reverting the examples:

* remove the 'bindExamples()' method from 'GezzyServletModule'
* remove the line 'new HelloModule(),' from
  'GezzyServletContextListener'
* delete all 'Hello' prefixed classes