Replace instances of 'hash' with 'object' in documentation

Context: https://twitter.com/mvirkkunen/status/506796515982311424

Many of us programmers know what "hashes" are in the general sense, but the word is not part of the JavaScript vernacular and could be unfamiliar to newcomers. This PR replaces instances of "hash" with "object" in various markdown documents.

This confuses the implementation strategy for the purpose of the thing. The configuration file uses an object literal, but the thing itself is a mapping between dependencies and version ranges.