Patch aws-sdk's aws/core.rb to avoid failed autoloads.

This fixes LOGSTASH-1718.
Add test coverage for LOGSTASH-1718

This new test verifies that aws-sdk can autoload constants correctly.

I verified this test *fails* before the fix is applied and passes after
it is applied.
Merge pull request #923 from jordansissel/LOGSTASH-1718

Fix aws-sdk require problems.
Adding cidr filter checks
adding tests for extractnumbers filter
Adding tests for urldecode filter
Adding spec tests for sumnumbers filter
Add spec test for gelfify and make it actually work
Merge pull request #927 from electrical/cidr_spec

Adding cidr filter checks
Merge pull request #928 from electrical/extractnumbers_spec

adding tests for extractnumbers filter
Merge pull request #929 from electrical/urldecode_spec

Adding tests for urldecode filter
Merge pull request #930 from electrical/sumnumbers_spec

Adding spec tests for sumnumbers filter
Merge pull request #931 from electrical/gelfify_spec

Gelfify spec
Merge branch 'master' of https://github.com/logstash/logstash