Merge pull request #5286 from RosettaCommons/roccomoretti/DEER_abs
Fix potential rounding in DEEROverlapMethod
Clang 10 indicates issues with the abs() being used, as it's the C library (integer) abs() function, rather than the overloaded C++ library one. ("using integer absolute value function 'abs' when argument is of floating point type"). Prepending std:: should fix this.
(If integer truncation is desired, then we should be more explicit about it.)