Getting demo to run, why is it so difficult. Readme needs an update.

[surfer190]

Steps:

1. Download gradle version required 2.1, using manual method as Android Studio is bad in that respect.
2. Change runProguard false to minifyEnabled false in sampleapp/build.gradle and multilevelexpindlistview/build.gradle
3. Library projects cannot set the ApplicationId, so have to remove that line from multilevelexpindlistview/build.gradle