added test for using the latest of two versions

test/slow/install two versions and use the latest one

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+set -e
+. ../../nvm.sh
+
+# Remove the stuff we're clobbering.
+[ -e ../../v0.10.25 ] && rm -R ../../v0.10.25
+[ -e ../../v0.10.26 ] && rm -R ../../v0.10.26
+
+# Install from binary
+nvm install 0.10.25
+nvm install 0.10.26
+
+# Check
+[ -d ../../v0.10.25 ]
+[ -d ../../v0.10.26 ]
+
+# Use the first one
+nvm use 0.10.25
+
+# Use the latest one
+nvm use 0.10
+node --version | grep v0.10.26