Fix bug tallying reaction rates with multipole
Created by: paulromano
This pull request addresses the bug described in #853 (closed). I've extended the multipole test to include some tallies too so we cover the case that produced the bug in the first place.
Unrelated to the multipole fix -- I've changed how pugixml is built (always assuming the C++ compiler has long long support). The problem is that when you use the CXX_STANDARD target property in CMake, it doesn't necessarily know what flags to use for all compilers. For example, I've found that for both the IBM XL compilers and PGI compilers, it doesn't work.