Use .NET Core 1.1

tests/SkiaSharp.NetCore.Tests/project.json

@@ -29,10 +29,10 @@
     },
     "testRunner": "nunit",
     "frameworks": {
-        "netcoreapp1.0": {
+        "netcoreapp1.1": {
             "dependencies": {
                 "Microsoft.NETCore.App": {
-                    "version": "1.0.0"
+                    "version": "1.1.0"
                 }
             },
             "imports": [
@@ -45,6 +45,9 @@
         "win7-x86": { },
         "osx.10.10-x64": { },
         "osx.10.11-x64": { },
-        "ubuntu.14.04-x64": { }
+        "ubuntu.14.04-x64": { },
+        "ubuntu.14.10-x64": { },
+        "ubuntu.16.04-x64": { },
+        "ubuntu.16.10-x64": { }
     }
 }