cosmetic: map contains more than one world

### Problem description

When you call the map view, you get this (I assume) OpenStreetMap world map. The problem is that it's tiled - so my default view is this weird one containing about 2.0 worlds :-)

I just think it should be tightened up to only show one world - I can see no reason for anyone to want to see more than one. Also, if I click the "+" sign to expand it - that one click then makes the map too big and I lose countries. It should be normalized to fit the window (at least to begin with)

BTW, having some way to call a map in a standalone tab would be great: you could make a NOC map view out of it :-)
### Steps to reproduce the problem
1. make a map
2. 2.0 worlds await
### Environment
- Graylog Version: graylog-server-2.0.0-4.beta.3.noarch
- Elasticsearch Version: elasticsearch-2.3.1-1.noarch
- MongoDB Version: mongodb-2.6.11-1.el7.x86_64
- Operating System: CentOS-7
- Browser version: Firefox/45