Run tests on Travis (#151)

This CR introduces changes in the testing on Travis. Now,
mono 5.2.0 used
C# tests running on push
native libraries being extracted from nuget package and it resolves #146 Downside of this - new version of nuget should be published before source code with upgrade pushed into the source control
The test Should_ReduceMean() was broken by this commit, so I returned initial behavior

Author: Dorokhov

.travis.yml

@@ -1,15 +1,15 @@
 language: csharp
 solution: TensorFlowSharp.sln
 script:
-  - wget "http://ci.tensorflow.org/view/Nightly/job/nightly-libtensorflow/TYPE=mac-slave/82/artifact/lib_package/libtensorflow-cpu-darwin-x86_64.tar.gz"
-  - tar xzvf libtensorflow-cpu-darwin-x86_64.tar.gz lib/libtensorflow.so
-  - mkdir -p native
-  - cp lib/libtensorflow.so native/libtensorflow.dylib
-  - cp lib/libtensorflow.so native/
+  - tsh_version=1.3.0
+  - wget "https://www.nuget.org/api/v2/package/TensorFlowSharp/$tsh_version"
+  - tar xzvf $tsh_version native
   - msbuild /t:Restore $TRAVIS_BUILD_DIR/TensorFlowSharp.sln
   - cd $TRAVIS_BUILD_DIR/
   - msbuild /p:Configuration=Release TensorFlowSharp.sln
   - cp -R $TRAVIS_BUILD_DIR/native/libtensorflow.dylib $TRAVIS_BUILD_DIR/tests/TensorFlowSharp.Tests/bin/Release/libtensorflow.dylib
-  - sh $TRAVIS_BUILD_DIR/build.sh
-mono: "5.0.0"
+  - cp -R $TRAVIS_BUILD_DIR/native/libtensorflow.dylib $TRAVIS_BUILD_DIR/tests/TensorFlowSharp.Tests.CSharp/bin/Release/libtensorflow.dylib
+  - cd $TRAVIS_BUILD_DIR/packages/xunit.runner.console.2.2.0/tools
+  - mono --arch=64 xunit.console.exe "$TRAVIS_BUILD_DIR/tests/TensorFlowSharp.Tests/bin/Release/TensorFlowSharp.Tests.dll" "$TRAVIS_BUILD_DIR/tests/TensorFlowSharp.Tests.CSharp/bin/Release/TensorFlowSharp.Tests.CSharp.dll"
+mono: "5.2.0"
 os: "osx"

TensorFlowSharp/OperationsExtras.cs

@@ -31,7 +31,11 @@ TFOutput ReduceDims (TFOutput input, TFOutput? axis = null)
 			if (shape.IsFullySpecified) {
 				// The python code distinguishes between tensor and sparsetensor
 
-				return this.Const (shape.ToIntArray (), TFDataType.Int32);
+				var array = new int [shape.NumDimensions];
+				for (int i = 0; i < array.Length; i++)
+					array [i] = i;
+
+				return this.Const (array, TFDataType.Int32);
 			}
 			// Otherwise, we rely on Range and Rank to do the right thing at run-time.
 			return Range (Const (0), Rank (input), Const (1));