Separate normalization process
Normalize property names for new style names
Use new names to normalize property values
Add s:is_ui_property_name
Use s:is_ui_property_name
Add s:is_non_ui_property_name
Use s:is_non_ui_property_name
Improve the error message on missing "sfile"
Improve the error message on unknown property
Use new names to define interface key mappings
Remove a never executed clause
Use new names in "pattern" utilities
Use new names in "select-function" utilities
Fix typos
Add tests on old property names
Update the document for new style properties
Merge branch 'use-consistent-property-names'

Close gh-11.
Reject gh-8 and gh-9.
Add release notes on 0.4.0
Bump up version to 0.4.0
Merge branch 'prepare-0.4.0'