[lec12] Add short exercises for parser combinator lecture

README.md

src/main/scala/parsers/Combinators.scala

src/main/scala/parsers/ContactParser.scala

src/main/scala/parsers/lib/ContactParser.scala

src/main/scala/parsers/lib/NonEmptyList.scala

src/main/scala/parsers/lib/ParseResult.scala

src/main/scala/parsers/lib/Parser.scala

src/main/scala/parsers/lib/ParserOps.scala

src/main/scala/parsers/lib/Parsers.scala

src/main/scala/parsers/lib/Typeclasses.scala

src/test/scala/parsers/AddressParserSpec.scala

src/test/scala/parsers/Many1Spec.scala