add c++ benchmarks folder to c++ tests framework
fix cell_lists benchmark

it was stopping prematurely
formatting
numerical robustness
Merge pull request #96 from sniblett402/periodic_boundaries

Implementing periodic boundaries for rigid bodies
add coverage to cpp tests using cmake and gcov
extend hs-wca cpp test
add option to plot hswca potential
Merge remote-tracking branch 'origin/master' into hs_wca_again
truncate energy within soft shell
return early sometimes
add documentation, add outline
change clashing name
switch from fHS-WCA to sf_HS_WCA_interaction
fix sign error, add plotting test
add more points to test
update and comment out printing part in test
add cpp test comparing s and sf versions of HS-WCA
add test against direct simple implementation, fix gradient confusion
merge python and cpp coverage reports