Various minor changes

Some stack improvements

Queue implementation

Queue implementation

Removed the various value-type macros

str_at() enhanced to index from the end

Stack implementation

Stack implementation

Stack implementation

Small fixes

Small fixes

128-bit multiplication sans 128-bit types implemented

Hashtab implementation

Hashtab implementation

Hashtab implementation

maps/stack/queue scaffoldings

Added backtrace capability to invariants

String implementation continued

String implementation continued

String implementation continued

String implementation continued

Clang format