Remove the matrix for Travis CI

[yeesian]

it is a deprecated alias for jobs (see https://juliadocs.github.io/Documenter.jl/stable/man/hosting/#Travis-CI for details)

Ref. #134. (I don't know if it fixes it yet)

I have generated a new SSH Deploy Key called "Documenter.jl Deploy Key" and followed https://juliadocs.github.io/Documenter.jl/stable/man/hosting/#travis-ssh to add an env variable called DOCUMENTER_KEY to Travis CI. I'll remove the old SSH Deploy Key called "documenter" once we manage to get things up and running with the new key.

[coveralls]

Coverage remained the same at 92.389% when pulling cc16c27 on yeesian-remove-travis-yml-matrix into e944323 on master.

[coveralls]

Coverage remained the same at 92.389% when pulling bc6d2c6 on yeesian-remove-travis-yml-matrix into e944323 on master.

[visr]

Ah, the doc build is crashing because we are using download_verify from BinaryProvider:

[ Info: Downloading https://github.com/yeesian/ArchGDALDatasets/blob/master/data/point.geojson?raw=true to /home/travis/build/yeesian/ArchGDAL.jl/test/data/point.geojson...
ERROR: LoadError: MethodError: no method matching #tee#13(::Nothing, ::Base.PipeEndpoint, ::typeof(tee), ::OutputCollector)
Closest candidates are:
  #tee#13(!Matched::Bool, ::IO, ::typeof(tee), ::OutputCollector) at /home/travis/.julia/packages/BinaryProvider/U2dKK/src/OutputCollector.jl:290
Stacktrace:
 [1] OutputCollector(::Cmd; verbose::Bool, tail_error::Bool, tee_stream::Base.PipeEndpoint) at /home/travis/.julia/packages/BinaryProvider/U2dKK/src/OutputCollector.jl:136
 [2] download(::String, ::String; verbose::Bool) at /home/travis/.julia/packages/BinaryProvider/U2dKK/src/PlatformEngines.jl:610
 [3] download_verify(::String, ::String, ::String; verbose::Bool, force::Bool, quiet_download::Bool) at /home/travis/.julia/packages/BinaryProvider/U2dKK/src/PlatformEngines.jl:688
 [4] top-level scope at /home/travis/build/yeesian/ArchGDAL.jl/test/remotefiles.jl:42
 [5] include(::Function, ::Module, ::String) at ./Base.jl:380
 [6] include(::Module, ::String) at ./Base.jl:368
 [7] exec_options(::Base.JLOptions) at ./client.jl:296
 [8] _start() at ./client.jl:506
in expression starting at /home/travis/build/yeesian/ArchGDAL.jl/test/remotefiles.jl:35

This function has moved to Pkg:
https://github.com/JuliaLang/Pkg.jl/blob/4270a54130d70a3b93419d4ce6908f0d999bec59/src/PlatformEngines.jl#L963
JuliaPackaging/BinaryProvider.jl#190

So we should use that one, perhaps that also helps with the error.

[yeesian]

Wow, thank you!