Compile with libcurl support

[yeesian]

To support remote requests

[visr]

Yeah so from these two lists there are 15 formats that use libcurl:

• http://www.gdal.org/formats_list.html
• http://www.gdal.org/ogr_formats.html

In the GDAL tarball from the releases page, in logs/GDAL.log, you can see that it is indeed build without cURL support:

GDAL is now configured for x86_64-apple-darwin14
  cURL support (wms/wcs/...):no

I guess it would be the easiest if someone created a CURLBuilder and switched https://github.com/JuliaWeb/LibCURL.jl to use it?

[visr]

Great, it has been done, now we just need to configure it as a dependency. Might be best done in one go with #3.

https://github.com/JuliaWeb/LibCURLBuilder

[visr]

While we currently build with --with-curl=$prefix/bin/curl-config, it doesn't seem to be working properly, as noted also in the build.log:

        found libcurl version 7.64.1
checking for curl_global_init in -lcurl... no
  cURL support (wms/wcs/...):no

Too bad, since this would enable many drivers. However I don't want it to hold up JuliaGeo/GDAL.jl#66 any longer.

[visr]

Fixed in #12