Change the background colour of the search entries in the Find and Replace dialogs according to the search results like in the toolbar search field.
Add images to the 'Replace' and 'Replace and Find' buttons in the Replace dialog.
Minor cleanups in search.c.

git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/trunk@3605 ea778897-0a13-0410-b9d1-a72fbfd435f5