Add load_plugin_textdomain

If there is no `load_plugin_textdomain` then the translations will not be loaded from the languages folder.
Merge pull request #128 from grappler/patch-1

Add load_plugin_textdomain
Update ChangeLog.md

Just a typo
Merge pull request #158 from Tintazul/patch-1

Update ChangeLog.md
Merge remote-tracking branch 'official/master'