Fix relative paths in batch files.

Build.cmd

@@ -1,3 +1,3 @@
 @echo off
-powershell -ExecutionPolicy ByPass .\build\Build.ps1 -restore -build %*
+powershell -ExecutionPolicy ByPass %~dp0build\Build.ps1 -restore -build %*
 exit /b %ErrorLevel%

CIBuild.cmd

@@ -1,3 +1,3 @@
 @echo off
-powershell -ExecutionPolicy ByPass .\build\Build.ps1 -restore -build -test -sign -pack -ci %*
+powershell -ExecutionPolicy ByPass %~dp0build\Build.ps1 -restore -build -test -sign -pack -ci %*
 exit /b %ErrorLevel%

Restore.cmd

@@ -1,3 +1,3 @@
 @echo off
-powershell -ExecutionPolicy ByPass .\build\Build.ps1 -restore %*
+powershell -ExecutionPolicy ByPass %~dp0build\Build.ps1 -restore %*
 exit /b %ErrorLevel%

Test.cmd

@@ -1,3 +1,3 @@
 @echo off
-powershell -ExecutionPolicy ByPass .\build\Build.ps1 -test %*
+powershell -ExecutionPolicy ByPass %~dp0build\Build.ps1 -test %*
 exit /b %ErrorLevel%