Titanium sdk 3.6-master first stab to support android Lollipop material design MIN-SDK-VERSION:
<sdk-version>3.6.0.v20150129165610</sdk-version>
You will need to update your android tools and grab the android 21 version, you can do that via Studio.
Also you will need to install the master git to get the lasted bleeding edge sdk version:
$ titanium sdk install --branch master --default
Do not forget to change the sdk version in tiapp.xml according.
<sdk-version>3.6.0.v20150129165610</sdk-version>