This allows clients to send batched up events in the same format as
before (or to continue to send single events). We can switch the
default format to an array in 1.4.x.

This reverts commit a628ba1b.

This reverts commit 46ee0ce1.

This reverts commit 90d6490f.

This reverts commit 088afa6d.

This reverts commit 3c1a23e7.

This reverts commit 258e53a4.

Fixes gh-1205

Fixes gh-873

For compatiblity with Angel streams we only need to set the content
type explicitly.

Fixes gh-873

This reverts commit 721fdc59.