Renamed Compiler* -> Engine*

CompilerException, CompilerConfig, CompilerConfigImpl, CompilerLog
Fixed bug in ParserConfigImpl: settings link pre-/postfix to null would result in NPE
Extracted superclass DefaultConfig and renamed DefaultConfigEn to DefaultConfigEnWp
Renamed CompiledPage -> ProcessedPage, made logs a child instead of a property, renamed log nodes to EngLog*, made them inherit from WtNode and only instantiatable through a factory
Renamed WtEngine -> WtEngineImpl and IWtEngine -> WtEngine
Fixed #10: Mantis #31: A WikiConfigImpl unmarshalled from XML is useless.

Also fixed warnings with new Eclipse Kepler IDE