format
fix: tr.600 (assign to 1x1 bigintmat)
test for tr.600
add quotient ring check
Added links to doxygen resources
Merge pull request #624 from surface-smoothers/normal.lib.add.quotientCheck

add quotient ring check to normal.lib
format
ok_l.lst -> ok_l.lst, ok_l2.lst
fix: missing parts (assign bigintmat) for tr.600
changed test sets ok_l, ok_l2
fix: conversion to FLINT over Q
fix: exclude all value in the ground field
fix: wrong handling of SW_RATIONAL
fix: use Prem instead of reduce
chg: more tests for char_series