Changes

README.md add section about device compatibility

To give potential users an estimate on which android devices the APDU proxy
may work, let's explain a bit about which Android releases have OMAPI and
which not. Let's also add a table with devices with which we have tested
the APDU proxy successfully.

Change-Id: I64459bbe2920c7381ab75e422bf317ad21c8b8cc
Related: OS#6367