DMN15 — Typos in the XMI files

I found two typos in the XMI files:
1. In the DMNDI12.xmi, lines 510-512:

```
<packagedElement xmi:type="uml:Class" xmi:id="_18_1_f7a0369_1441612964861_428140_5975"
name="DC::Style"
isAbstract="true"/>
```

The class cannot refer to dc:Style as such class does not exist. The XSD refers to di:Style.

2. In the DMN12.xmi, lines 956-958:

```
<ownedAttribute xmi:type="uml:Property" xmi:id="_17_0_3_1_42401a5_1375643571589_681805_3414"
name="input
"
visibility="public"
```

Attribute name includes an encoded newline character (`\n`) which is not present in the XSD.