fix doc url

See: https://github.com/springmeyer/travis-coredump/blob/master/.travis.yml

Also use assertEquals(), since assertSame() tests for object identity.

Normalizing top-level documents as arrays will allow single and multi-document checks to be more flexible. This will not extend to embedded documents, where we'll still need to be explicit.

Additionally, assertSameDocuments can now operate on any array or Traversable without needing to set its own type map.

Unless the operation returns a scalar or custom value (e.g. Count, CreateIndexes), we should explicitly convert documents to stdClass instances to return. This will ultimately be made configurable once PHPLIB-112 is implemented.

A manual cast (of arrays to objects) was also necessary until PHPC-318 is implemented.