Stop crash caused by internal Android exception stopping scan

This is a test release intended to fix the issue reported in #701. Note: this release does NOT include changes from 2.14.1-beta1.

To use this release, you must download the aar file attached to this release, and configure it with your project like so:

• Edit your innermost build.gradle file to add the beta library AAR as a dependency like so:

      dependencies {
        compile 'android-beacon-library:2.15.1-beta2@aar'
      }

• Create a /libs folder next to the build.gradle above, then download and copy the aar file attached to this release into this folder.