Make signal-id installable.
Allow file name to be passed as cube.
SNR cube now a property.
Use sigma_rob to calculate scales.
Add new axes instead of reshaping.
Update testing values for sigma_rob
Clean-up of loading data in/returning cube objects.
Added class properties.
Removed duplicated return functions.
Revert "Removed duplicated return functions."

This reverts commit 2bcba390c111efa56b1a8f47fa2e3cc06b2f3ef2.
Revert "Added class properties."

This reverts commit 0d1e2ece935337b0aa36cf55200b0ba0e52d04ba.
Revert "Clean-up of loading data in/returning cube objects."

This reverts commit 79e5ddc1cdf3ca5dcd3f0a5dfb2a62063a5ffaeb.
Fixes for sigma_rob.
Revert testing values.
Moved external functions to utils.
Merge pull request #23 from e-koch/master

Added install script; use iterative outlier rejection to calculate scale