fix for issue #118
#118 fix - tslater
Merge pull request #123 from sigmundfridge/master

Fix for #118.
Added finalize for checkStatement.  Fix #122
Null safeguards Issue #127
Drop indices and migrate relationship columns

Added a helper to drop indicies because migrations were failing when trying to recreate indicies.
Noticed relationship data wasn't being copied over, so added it back in with a couple of tweaks we needed.
Merge pull request #129 from jasper-ch-chan/master

Null safeguards Issue #127
Merge pull request #128 from jcarroll3/master

Drop indices and migrate relationship columns
fixing warnings
fixing static analyzer errors
Better error handling

Creates a custom error if we detect not enough information to perform migration.

Also, don't override error if we already set it.
Errors by reference

As a caller of this method in the parent app, I would like to inspect the error in more detail.
travis testing
travis testing
Merge pull request #130 from jcarroll3/warningsAndStaticAnalyzerFixes

Warnings and static analyzer fixes
Merge pull request #131 from jcarroll3/createCustomError

Better error handling
Merge pull request #132 from jcarroll3/errorsByReference

Errors by reference
Revert "Warnings and static analyzer fixes"
Merge pull request #134 from project-imas/revert-130-warningsAndStaticAnalyzerFixes

Revert "Warnings and static analyzer fixes"
Wrapper functions to support non-NSError handling