LCMS1 replaced with LCMS2

  * Adds support for LCMS2, fixes #343.
  * Removes support for LCMS1 (security)
  * Includes revised support for LAB color mode
     * Conversions to and from LAB color using LCMS2 work. 
     * Reading/writing LAB color space tiffs works. 
     * Internal representation of LAB color mode a and b channels has changed to 0-255, 128 is neutral.