Renamed class Selector to FroastTools

Selector is basically a collection static methods that form the
basis of the froast tool commands. Thus, FroastTools is a more suitable
name (also, not all of the methods are based on ROOT's TSelector).
Fixed error in online help for "froast map-multi"
Added "froast filter-multi"
Added input event-list option to "froast filter-multi"
Added Param::operator% and extended Param::operator()
Added logLevel methods to FroastTools and enum LogLevel to LinkDef
Made build compatible with ROOT-6