Travis: Disable Windows/MinGW build replaced by AppVeyor/MSVC

[ci skip]

.travis.yml

@@ -15,7 +15,6 @@ env:
   - GODOT_TARGET=osx
   - GODOT_TARGET=x11
   #- GODOT_TARGET=android
-  - GODOT_TARGET=windows
 
 matrix:
   include:
@@ -29,16 +28,12 @@ matrix:
       env: GODOT_TARGET=android
     - os: osx
       env: GODOT_TARGET=x11
-    - os: osx
-      env: GODOT_TARGET=windows
     - compiler: gcc
       env: GODOT_TARGET=iphone
     - compiler: gcc
       env: GODOT_TARGET=osx
     - compiler: clang
       env: GODOT_TARGET=android
-    - compiler: clang
-      env: GODOT_TARGET=windows
     - compiler: clang
       env: GODOT_TARGET=x11
 
@@ -61,15 +56,6 @@ addons:
       - libxinerama-dev
       - libxrandr-dev
 
-      # For cross-compiling to Windows.
-      - binutils-mingw-w64-i686
-      - binutils-mingw-w64-x86-64
-      - gcc-mingw-w64-i686
-      - gcc-mingw-w64-x86-64
-      - g++-mingw-w64-i686
-      - g++-mingw-w64-x86-64
-      - mingw-w64
-
       # For style checks.
       - clang-format-3.9