Adding more general streaming of variables
Adding real-life function that needs work
Merge branch 'master' of https://github.com/GuylainGreer/manifolds

Conflicts:
	variables.hh

Merging?
Streaming UnaryMinus
Changing priority again
Expanding multiplication of additions
metafunction queries
Expanding compositions of polynomials and additions
upping max simplification level
Monster of a test case
Upping template depth