type constructors in dynamic types are now uniquely represented by the
descriptor of their TD_ (type definition) function

for TA_RootVar in substitute), prevent exponential use of time in function
build_inequalities

in function get_command

exported, also export label with d prefix for strict constructor and
fix name for label with n prefix

typechecker or overloading header files to this file

Now the parser removes the offisde poistions from the stack instead of the scanner.