Sped up THnSparse data access (per dabercro's suggestion). Moved some THn helper functions around; more performance improvements to come
Merge branch 'master' of https://github.com/dabercro/MutualInformation

Conflicts:
	histEntropy.hh - fixed
added check of minusInfinity < logProb
Merge pull request #5 from sidnarayanan/master

speed