Added gitignore

Unity.gitignore

+/[Ll]ibrary/
+/[Tt]emp/
+/[Oo]bj/
+/[Bb]uild/
+/[Bb]uilds/
+/Assets/AssetStoreTools*
+
+# Autogenerated VS/MD/Consulo solution and project files
+ExportedObj/
+.consulo/
+*.csproj
+*.unityproj
+*.sln
+*.suo
+*.tmp
+*.user
+*.userprefs
+*.pidb
+*.booproj
+*.svd
+
+
+# Unity3D generated meta files
+*.pidb.meta
+
+# Unity3D Generated File On Crash Reports
+sysinfo.txt
+
+# Builds
+*.apk
+*.unitypackage