Tidying code (no functional change)
Only try to delete attributes if they exist
Default as for many-to-many self-associations

Default as for many-to-many self-associations v2
Typos and spacing
Fix wrong identifier pt 1
Fix wrong identifier pt 2
Tests for many-to-many self-associations
Damn tabs get everywhere
Avoid merge combining data types
Tests use promises
Throw error where 'as' not defined
Merge pull request #1749 from overlookmotel/fix-many-to-many-self-associations

Fix many-to-many self-associations