AppVeyor: increment build number with pull requests, in order to avoid conflicts (#503)

* AppVeyor: increment build number with pull requests, in order to avoid conflicts

* .appveyor.yml: consistent indentation

.appveyor.yml

@@ -2,20 +2,17 @@ version: '{build}'
 
 image: Visual Studio 2015
 
-pull_requests:
-  do_not_increment_build_number: true
-
 skip_branch_with_pr: true
 
 clone_depth: 1
 
 init:
-- ps: Update-AppveyorBuild -Version "build-$env:appveyor_build_number-$($env:appveyor_repo_commit.substring(0,7))"
+  - ps: Update-AppveyorBuild -Version "build-$env:appveyor_build_number-$($env:appveyor_repo_commit.substring(0,7))"
 
 build_script:
-- cmd: >-
-    src\BuildAll.cmd
-    exit %errorlevel%
+  - cmd: >-
+      src\BuildAll.cmd
+      exit %errorlevel%
 
 artifacts:
   - path: output\pkg\*\*