KT-1545, KT-3161 KDoc basic lexer, parser, formatter and highlighter

Basic implementation of KDoc lexer, parser and formatter (now support only striping leading asterisks, @tag names and [[WikiLinks]]).

It also fixes JetFormattingModelBuilder.createModel bug (see http://devnet.jetbrains.com/thread/444902 and http://devnet.jetbrains.com/thread/444830)

Building & all tests passed.