Initialize PRNG for more secure random numbers

Explained and taken from here:
http://android-developers.blogspot.de/2013/08/some-securerandom-thoughts.html
Fix the multi-select in ListView for 4.1.1+

A hack to fix a bug in Android, see details:
http://code.google.com/p/android/issues/detail?id=35885
Upgrade to target android-18