Move removeEquivalentProperties functions to EditingStyle
https://bugs.webkit.org/show_bug.cgi?id=131093

Patch by Zsolt Borbely <zsborbely.u-szeged@partner.samsung.com> on 2014-04-30
Reviewed by Csaba Osztrogonác.

A follow-up to r167967. Use single line declaration for template methods.

* editing/EditingStyle.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@168011 268f45cc-cd09-0410-ab3c-d52691b4dbfc