added MERThumbnailKit 2.2.4
Merge remote-tracking branch 'upstream/master'
fix MERThumbnailKit 2.2.4 podspec
remove nonexistent ReactiveFoundation dependency
Merge remote-tracking branch 'upstream/master'
fix MERThumbnailKit 2.2.4
added Private directory to spec.source_files
Merge pull request #11839 from MaestroElearning/master

added MERThumbnailKit 2.2.4