improve the integation code

this should make the integration code for hrixs more readable, and also fixes a bug.

added 4 commits

• aa6bc003 - simplify integration
• 90631a58 - brutal simplification of integration
• 11218377 - using bincount instead of histogram for integration
• ad1579a3 - improve readability of integration

Compare with previous version

merged

mentioned in commit de92cf11