First attempt at Strahler function.
Remove weight from function signature.
Update the metadata.
Add javadoc.
Store results.
Add function to the activator.
Update function signature.
Rename to ST_StrahlerStreamOrder.
Update description.
Fix the error message.
Remove orientation.
Add unit test.
Add BD Carthage link.
Simplify exception list.
Fix failing build due to upstream changes.
Merge branch 'master' into feature/Strahler

This fixes an otherwise failing build due to upstream changes.
Merge pull request #25 from agouge/feature/Strahler

Add ST_StrahlerStreamOrder