fix Issue #8953- add Extension Manager support for localized extension package metadata.
update localization example for reference
update localization readme for reference
as requested per code review
changes per code review
Merge remote-tracking branch 'origin/master' into bchin/localize-package-metadata
per code review, overlay first by shortlang, then by lang.
Merge remote-tracking branch 'origin' into bchin/localize-package-metadata
whitelisting properties to overlay; remove keyword concatenation with root language
add top-level key to package.json to avoid collisions
changes per code review
adding unit tests
fix #9114
add class to #editor-holder for split orientation
Merge remote-tracking branch 'upstream/master'
Tweaked pane separator styling to make sure that horizontal separators look good.
Merge pull request #9162 from adobe/jeff/add-splitview-classes

Add class to #editor-holder for split orientation
Merge pull request #9147 from adobe/jeff/fix-9114

Fix bug #9114 - Don't MVM.updateLayout() until we're ready
changes as requested per code review
Further consolidate duplicated code in a unit test