Update travis config

.travis.yml

@@ -1,4 +1,5 @@
 language: csharp
+dótnet: 2.0.0
 sudo: required
 dist: trusty
 addons:
@@ -6,10 +7,6 @@ addons:
     sources:
     packages:
 install:
-  - sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ trusty main" > /etc/apt/sources.list.d/dotnetdev.list' 
-  - sudo apt-key adv --keyserver apt-mo.trafficmanager.net --recv-keys 417A0893
-  - sudo apt-get update
-  - sudo apt-get install dotnet-dev-1.0.4 -y
 script: 
   - dotnet restore src
   - dotnet build -c Debug src