[WIP] Introduce attribute accessor with reader/writer objects
[wip] remove obsolete specs; fix attribute specs
[WIP] Refactor Collection to use custom writer
[WIP] Update Hash to use coercible writer
[WIP] Allow passing custom reader/writer classes to attribute builder
[WIP] Restore default value in Attribute
[WIP] Refactor EmbeddedValue to use custom writers
[WIP] Update EV writer unit specs
[WIP] Fix Attribute.determine_type spec
[WIP] Fix EmbeddedValue.determine_type specs
[WIP] Fix EmbeddedValue.merge_options spec
[WIP] Fix Attribute#define_reader_method spec
[WIP] Fix Attribute#define_writer_method spec
[WIP] Remove obsolete EmbeddedValue#coerce spec
[WIP] Fix EmbeddedValue::OpenStructWriter specs
[WIP] Fix Hash.merge_options spec
[WIP] Move key_type and value_type readers to Hash::CoercibleWriter
[WIP] Fix ValueObject.attribute specs
Fix Attribute.determine_type specs
Adjust flay thresholds