new CalibrationPreference

• add marks to OneDimensionRulerView
• new CalibrationPreference:

<com.github.anastr.rulerview.CalibrationPreference
        android:key="ruler_coefficient"
        android:title="Calibration"
        android:summary="calibration ruler to real measurement and save the value to pass it to other ruler views" />

Initial

V1.0.0

Update README.md