hash table rewrite first working version
minor changes
added code to estimate the memory that could potentially be saved
when storing the variable list of components only once
for all components sharings the same list
bit stuffing to remove clauses_ofs_ from BasePackedComponent
now store number of variables instead,
also in packed components the clause data starts right after the
last variable data bit
small reduction of the size of a base packed component
by bit stuffing the delete_permitted bit
cleanup commit