Fixes #3 using Option 1A, as described in the Github issue.  Note that
this removes support for Android 1.5 (API Level 3) devices, in order to
support runtime testing of platform version to use either the
SystemClock.elapsedRealtimeNanos() and
Location.getElapsedRealtimeNanos() to calculate TTFF for Android 4.2 and
up, while using System.currentTimeMillis() and Location.getTime() for
Android 1.6 to 4.1.  A version supporting Android 1.5 will need to be
maintained in a new branch.  Two APKs (this branch, and separate 1.5
only branch) will need to be uploaded to Google Play.  Note that the
version number isn't bumped in this commit, since there is at least one
other edit that will likely be released along with this commit.
Merge pull request #4 from barbeau/issue3

Fixes #3 using Option 1A, as described in the Github issue.