for install, don't call abort if invoked with iex, because that will …

…kill the ps session

bin/install.ps1

@@ -10,7 +10,11 @@ echo 'initializing...'
 iex (new-object net.webclient).downloadstring($core_url)
 
 # prep
-if(installed 'scoop') { abort "scoop is already installed. run 'scoop update' to get the latest version." }
+if(installed 'scoop') {
+    write-host "scoop is already installed. run 'scoop update' to get the latest version." -f red
+    # don't abort if invoked with iex——that would close the PS session
+    if($myinvocation.commandorigin -eq 'Internal') { return } else { exit 1 }
+}
 $dir = ensure (versiondir 'scoop' 'current')
 
 # download scoop zip