tfs: windows build

build/tfs/win32/lib.ps1

@@ -6,7 +6,9 @@ $env:HOME=$env:USERPROFILE
 if (Test-Path env:AGENT_WORKFOLDER) {
 	$env:USERPROFILE="${env:AGENT_WORKFOLDER}\home"
 	$env:HOME="${env:USERPROFILE}"
+	$env:npm_config_cache="${env:USERPROFILE}\npm-cache"
 	New-Item -Path "$env:USERPROFILE" -Type directory -Force | out-null
+	New-Item -Path "$env:npm_config_cache" -Type directory -Force | out-null
 }
 
 # throw when a process exits with something other than 0