Fix final 0.4 deprecation warnings

[visr]

Also run Travis on 0.3 and use Compat in tests.

[visr]

Failing on 0.3.

INFO: Testing GeoJSON
ERROR: `dict2geojson` has no method matching dict2geojson(::Nothing)
 in dict2geojson at /home/travis/.julia/v0.3/GeoJSON/src/parser.jl:8
 in parse at /home/travis/.julia/v0.3/GeoJSON/src/parser.jl:72
 in include at ./boot.jl:245
 in include_from_node1 at loading.jl:128
 in process_options at ./client.jl:285
 in _start at ./client.jl:354
while loading /home/travis/.julia/v0.3/GeoJSON/test/runtests.jl, in expression starting on line 5

Can get back to it later. What is the plan for dropping 0.3 support?

[yeesian]

Apologies for the lack of activity on this package: I have a local branch that implements (and uses) the GeoInterface package, but didn't want to force the dependency. I can push it if you're interested.

1. The fix is to add dict2geojson(obj::Void) = nothing to parser.jl Edit: Sorry, didn't notice you've already fixed it. It seems that @compat should work
2. We should support v0.3 on this PR (because of #7), merge to master and tag in METADATA, before dropping support (i.e. GeoJSON v0.0.3 will be the last version to support julia 0.3)

[visr]

Sounds good to me. Thanks for the tip on @compat, I assumed that would have been taken care of by using Compat. Now it's passing on 0.3, I'm done.

[yeesian]

Thanks!