How to deal with ' or (&#39;) in CKeditor
You can turn off html encoding for CKeditor through UI (i.e >= 4.7)

Navigate to Administer >> Customize Data and Screens >> Display preferences

Scroll down until you see Configure CkEditor button. Click on it to view all the settings. Under Advance options add entities option as False(as shown in image) and save the form. 



Note: You will need to clear your browser cache to reflect the changes(and CiviCRM caches).