Created tests for group files
Added group file procedure and updated morris class to suit
Removed print statements
Added tests for scale_samples
Changed scale_samples to inplace numpy operation
Added raw data methods to the Sample class.
Added tests for Morris methods for getting scaled and unscaled samples
Corrected group/groups attribute error in Morris class
Updated Python example to include calls to Morris class
Updated shell example for morris to use Morris class
Changed tests for new group file format
Added group file module to Morris class and amended tests
Tidied up bugs in Morris class

- Corrected error message so that the trigger matched the message
- Formatted a print command message to accompany error raised when
variables in group file do not match those in the parameter file
- Remove scale samples from morris_groups procedure in Morris class
Updated example morris usage
Added example for Morris groups
Added example for morris optimal
Added regression tests using Morris and Ishigami
Updated regressions to ignore optimal

(rtol set high)
Separate Sample class out from morris class
Added teardown to regression tests to remove txt