Adding documentation for -isEqual and -description
Improving documentation
Improving documentation again
Fixing typos
Fixing TomDoc style
Merge pull request #146 from github/isequal-docs

Adding documentation for -isEqual and -description
Flip encounteredError
Reduce nesting
Use id<MTLTransformerErrorHandling>
Add explicit required
Fix style of blocks returning id
Improve documentation
Improve error handling interface, messages
Inline old MTLValueTransformerBlock
Rename MTLValueTransformationBlock to old name
Bubble up errors for malformed URLs
Fix reverse transformation documentation
Handle errors during object uniquing
Improve MTLTransformerErrorHandling docs
Rename error key