Initialization order matters

(cherry picked from commit 265616c4ac6103d9b091bc06590ffcb9cc0f337e)
Assets\Filters\Cssmin should implement Assets\FilterInterface

(cherry picked from commit bd0e085bc6dd637ba1e639d2be37e73224ae22d4)

Conflicts:
	ext/assets/filters/cssmin.c
Assets\Filters\Jsmin should implement Assets\FilterInterface

(cherry picked from commit 30461a5f495da880643455a8a11d9c53ece6ee73)

Conflicts:
	ext/assets/filters/jsmin.c
Updated README.md (#1525)

(cherry picked from commit 69986d6b8e4c70ceddd28c62094d1247a637eb03)

Conflicts:
	README.md
Merge pull request #1539 from sjinks/filterinterface

Filters\{Css,Js}min should implement FilterInterface