Add ability to set the integration grid size when integrating in the square DP, addresses #65. Still need to consider the automatic division of the sqDP around narrow resonances in m12 (and hence mPrime).

git-svn-id: svn+ssh://phab.hepforge.org/source/laurasvn/trunk@310 30227d83-a2f9-49e9-9e98-657c83b2c86a