Rethink icons for items

Reviewers claimed that the icons for the items in the search results are "too similar and too detailed". Currently, there is also a change from "solutions" to "workflows", so that the "S" in the icon of workflows doesn't fit anymore. In general, there was the discussion if having only a letter and a different color for distinction gives a good indicator for browsing the different types of items we have (additionally the window style of the icons was not so well appreciated). Also, there will be a new type available ("Publications") and one type will change the name (from "Tools" to "Tools & services".

@wytrazek - What is your opinion on new icons for the different item types? Do you have some ideas on this?