Mark your calendars!   The Kindle version of my latest mystery thriller Empty Places will available this week at a discounted price of only 99 cents.    The 3-day Amazon Countdown promotion runs from May 15 to May 17 and offers a savings of $3.    Empty Places, which was named Thriller of the Month by e-thriller.com in March, tells the story of a war weary journalist who seeks redemption by solvi…