Minor improvements to README
Minor improvements to README

rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android