Add include guard and begin/end decls macros; Remove unused variable.
Update email address.
silence clang5 warning
silence GCC7 -Wformat-compare, -Wformat-truncation, and -Wimplicit-fallthrough; run ws.sh on some changed files
add note about center of masses
add notes describing the state of the simulate ...
bio.h is required for the definition of HANDLE ...
scale so that units are in meters