a) Updated CMake files to run tests and properly import other boost dependencies
b) Improved custom expectation facility and added test for same
c) fixed error when checking wasn’t being done on assignment
d) fixed error where lower bound was assumed to be 0
adjust rest of program accordingly
this should
a) factor casts out of checked operations and put them in safe_base_operations
b) simplify interval which will not explicitly check for overflows etc.
First milestone - make test_add_native pass all addition tests.
Making way for checked_float, checked_money, etc
a) factoring checked into checked_integer etc.
b) moved some tests from test_z to official tests
c) added test_rational which tests interoperability with boost::rational
d) moved safe_range to safe_integer_range
