adding preserveAspectRatio="xMidYMid meet" viewbox="0 0 16 16" to the sv...

...gs to fix rendering on IE10+

before:
![bildschirmfoto vom 2014-03-25 22 02 54](https://f.cloud.github.com/assets/1005065/2518147/e7707542-b460-11e3-9e41-0bed3f7b49a2.png)

after:
![bildschirmfoto vom 2014-03-25 22 02 25](https://f.cloud.github.com/assets/1005065/2518148/f10f292c-b460-11e3-9c46-33e9aa215cbc.png)