Remove TABs from src

Will also make selftest to check that they aren't introduced

Delete trailing whitespace in src/

This needs doing periodically, and is best done to a whole bunch of files
at once.

added library DatatypeSimps in src/datatype

The datatype package stores information about created datatypes in TypeBase.
This library accesses this information and provides useful theorems and simpsets.
These are especially designed to handle the explicit usage of case-constants. There is
support for

- simple rewrites for datatypes
- expanding universal and existential quantifiers
- lifting and unlifting case-constants (similar to COND_LIFT_ss for bool)
- congruence theorems for usage with the simplifier (warning: slow)
- moving case-splits to the top-level of equational theorems. This is useful for
e.g. transforming definitions into a form more handy for rewriting.