20241112

• vector/matrix/subspace templates now used for multiprecision integer versions mvector, mmatrix, msubspace instead of these being coded separately.
• vec and mat template classes now based on vector for scalar=int, long, bigint
• improve precision handling for special L-value computations
• added some utilities
• improvements to Compute_Euler()
• many (mostly minor) changes suggested by cppcheck
• switched more C-style arrays to STL vectors
• much code simplification using newer C++ idioms e.g. auto