Merge remote-tracking branch 'refs/remotes/base/master'

Conflicts:
	Project.toml
	README.md
	src/Polynomials.jl
	src/show.jl
	test/runtests.jl

Author: mileslucas

src/show.jl

@@ -97,6 +97,7 @@ types "text/plain" (default), "text/latex", and "text/html" are supported. By
 default, the terms are in order of ascending powers, matching the order in
 `coeffs(p)`; specifying `descending_powers=true` reverses the order.
 `offset` allows for an integer number to be added to the exponent, just for printing.
+`var` allows for overriding the variable used for printing.
 
 # Examples
 ```jldoctest
@@ -108,6 +109,8 @@ julia> printpoly(stdout, Polynomial([2, 3, 1], :z), descending_powers=true, offs
 1 + 3*z^-1 + 2*z^-2
 julia> printpoly(stdout, Polynomial([-1, 0, 1], :z), offset=-1, descending_powers=true)
 z - z^-1
+julia> printpoly(stdout, Poly([-1, 0, 1], :z), offset=-1, descending_powers=true, var=:x)
+x - x^-1
 ```
 """
 function printpoly(io::IO, p::P, mimetype=MIME"text/plain"(); descending_powers=false, offset::Int=0) where {T,P<:AbstractPolynomial{T}}