Exposing SuggestionMenu in DefaultSuggestionsDisplay via getter methods.

This is similar to the already exposed popupPanel so that developers
don't need to write a SuggestionDisplay from scratch just to customize
the suggestions menu (e.g. adding separators).

Change-Id: I7ed69d5c3ab0f61896497e1dc5fb2ae56d35e4d7
Make SDM compute the base url correctly

In order for GWT RPC to users need to be able to
set the base url for GWT RPC. This can be done by using a meta
tag, a baseurl tag in the dom or can be calculated dynamically.

This also fixes SDM usage for clients running of the local file
system like Phonegap clients, since they do not fail to calculate the
base url for their server anymore.

Bug: issue 8941, issue 8938
Change-Id: I4da959d27ea8f2537f0136ebab015c2e05e92f86