This is a proposal to introduce a cosmetic change in filter manager API so that runtime options can be passed to the filter() method. One of the use case (see MDLSITE-1026) is to pass the original format in which the text was inserted by the user (as is illustrated in the patch). Other options can be added later if/when needed.

Although this adds optional parameter $option (empty array by default), the patch has to modify all current filters because they extend common abstract base class. However note that the change itself is backward compatible as none of the current filter actually use the new parameter. This change is required if we want to solve MDLSITE-1026 and other similar issues.