Merge \"Enhance toString on ConferenceParticipant.\" into nyc-mr1-dev

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append("[ConferenceParticipant Handle: ");

        sb.append(mHandle);

        sb.append(Log.pii(mHandle));

        sb.append(" DisplayName: ");

        sb.append(mDisplayName);

        sb.append(Log.pii(mDisplayName));

        sb.append(" Endpoint: ");

        sb.append(mEndpoint);

        sb.append(Log.pii(mEndpoint));

        sb.append(" State: ");

        sb.append(mState);

        sb.append(Connection.stateToString(mState));

        sb.append("]");

        return sb.toString();

    }