CI Update

[CiaranOMara]

• Add Julia 1.3 to test matrix.
• Use the codecov flag in Travis instead of the manual code version.
• Pkg.instantiate after Pkg.develop.
• Add colour to make doc output.

[codecov-io]

Codecov Report

Merging #365 into master will decrease coverage by 0.07%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #365      +/-   ##
==========================================
- Coverage   40.79%   40.71%   -0.08%     
==========================================
  Files          18       18              
  Lines        3057     3058       +1     
==========================================
- Hits         1247     1245       -2     
- Misses       1810     1813       +3

Impacted Files	Coverage Δ
src/cairo_backends.jl	60.18% <0%> (-0.93%)	⬇️
src/svg.jl	71.17% <0%> (+0.04%)	⬆️

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[bjarthur]

i'd suggest waiting to merge this until after julia 1.3 comes out, and then not testing compose on 1.2 anymore. it might be awhile, as there is an RC5 planned.

[CiaranOMara]

I removed Julia v1.3 from the test matrix so as not to be held up by RC5.

[bjarthur]

was doing instantiate before develop causing a problem? i can't think of a reason why the order would matter.

[CiaranOMara]

I don't think the order would have caused any issues as both Pkg.develop() and Pkg.instantiate() should upgrade or downgrade packages as required, and I assume Pkg.jl would arrive at the same solution irrespective of order. In the end, this just matches the order in the Documenter.jl hosting example.