CCP4 / Windows / xia2 fix

Missing detectors.lib from the CCP4 cctbx / dxtbx installation was the problem - easily fixed:

C:\>cd \CCP4\6.4\lib\python2.7\site-packages\dxtbx

C:\CCP4\6.4\lib\python2.7\site-packages\dxtbx>mkdir data

C:\CCP4\6.4\lib\python2.7\site-packages\dxtbx>cd data

C:\CCP4\6.4\lib\python2.7\site-packages\dxtbx\data>cp \CCP4\6.4\share\xia2\Data\detectors.lib .

This should be mended in the next update.