Moved the library/ to library/leon/ so that IDE do not complain.

library/leon/annotation/isabelle.scala

library/leon/annotation/package.scala

library/leon/collection/List.scala

library/leon/collection/package.scala

library/leon/instrumentation/package.scala

library/leon/invariant/package.scala

library/leon/io/StdIn.scala

library/leon/lang/Bag.scala

library/leon/lang/Dummy.scala

library/leon/lang/Either.scala

library/leon/lang/Map.scala

library/leon/lang/Option.scala

library/leon/lang/Rational.scala

library/leon/lang/Real.scala

library/leon/lang/Set.scala

library/leon/lang/StrOps.scala

library/leon/lang/package.scala

library/leon/lang/synthesis/Oracle.scala

library/leon/lang/synthesis/package.scala

library/leon/lang/xlang/package.scala