define sin/cos on Dual to use sincos

[KristofferC]

A bit more efficient since sincos can share some computation between the sin and cos:

PR:

julia> d = Dual(1.0,2.0,3.0,4.0,5.0)

julia> @btime sin($d)
  10.050 ns (0 allocations: 0 bytes)
Dual{Nothing}(0.8414709848078965,1.0806046117362795,1.6209069176044193,2.161209223472559,2.701511529340699)

Master:

julia> d = Dual(1.0,2.0,3.0,4.0,5.0)

julia> @btime sin($d)
  13.638 ns (0 allocations: 0 bytes)
Dual{Nothing}(0.8414709848078965,1.0806046117362795,1.6209069176044193,2.161209223472559,2.701511529340699)

[codecov-commenter]

Codecov Report

Merging #561 (402ae93) into master (d033d2a) will increase coverage by 0.15%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #561      +/-   ##
==========================================
+ Coverage   84.95%   85.11%   +0.15%     
==========================================
  Files           9        9              
  Lines         844      853       +9     
==========================================
+ Hits          717      726       +9     
  Misses        127      127              

Impacted Files	Coverage Δ
src/dual.jl	73.55% <100.00%> (+0.45%)	⬆️
src/jacobian.jl	99.31% <0.00%> (+0.01%)	⬆️

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[KristofferC]

I don't know why this was here.

[chriselrod]

Might be worth doing similar for sincosd, at least if isdefined(Base, :sincos)?

[KristofferC]

Might be worth doing similar for sincosd

Base defines sincosd(x) as sind(x), cosd(x) so it doesn't seem there is any performance to gain there.