toolkit module (unfinished) and some others

- toolkit module is being renewed, functions are used where only one
output is needed; in beemat function, strain numbering convention is
corrected (previously: 11,22,33,12,23,13; now: 11,22,33,12,13,23) so
that it is consistent with Abaqus UMAT strain convention
- added key variable for xnode and tri_elem
- changed export into extract
- added 'failure' logical variable in tri elem

next:
- check glb_dee function convention see if it is consistent
- finish toolkit module upgrade