Fix Appveyor when it appends a random string (#16)

.appveyor.yml

@@ -1,8 +1,5 @@
 version: '{build}'
 
-# clone directory - avoids Appveyor appending a unique string: https://ci.appveyor.com/project/jarradh/nimbus-on2qu/build/59
-clone_folder: c:\projects\nimbus
-
 cache:
 - x86_64-4.9.2-release-win32-seh-rt_v4-rev4.7z
 - i686-4.9.2-release-win32-dwarf-rt_v4-rev4.7z
@@ -43,7 +40,7 @@ install:
   - koch boot -d:release
   - koch nimble
 build_script:
-  - cd C:\projects\nimbus
+  - cd C:\projects\%APPVEYOR_PROJECT_SLUG%
   - nimble install -y
 test_script:
   - nimble test