Make appveyor.yml more verbose, and other misc fixes.

appveyor.yml

@@ -6,16 +6,14 @@ environment:
   - TARGET: x86_64-pc-windows-msvc
     BITS: 64
 install:
-  - curl -sSf -o rustup-init.exe https://win.rustup.rs/
-  - rustup-init.exe -y --default-host %TARGET%
-  - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
+  - appveyor DownloadFile https://win.rustup.rs/ -FileName rustup-init.exe
+  - rustup-init.exe -yv --default-host %target%
+  - set PATH=%PATH%;%USERPROFILE%\.cargo\bin
   - if defined MSYS2 set PATH=C:\msys64\mingw%BITS%\bin;%PATH%
-  - rustc -V
-  - cargo -V
+  - rustc -vV
+  - cargo -vV
+  - git submodule update --init --recursive
 build: false
 test_script:
   - cargo build --verbose --all
   - cargo test --verbose --all
-branches:
-  only:
-    - master