multi: Error descriptions should be lowercase.

[atriviss]

As per https://github.com/golang/go/wiki/CodeReviewComments#error-strings,
error strings should not be capitalized

• Replace Capitalized by lower cases
• Also, at some places, made a judgement call and added a prefix

[davecgh]

Thanks for the PR. I haven't reviewed this yet, but the first thing I noticed is the commit will need to start with the prefix multi: since it touches multiple packages and the issue number must not be in the commits in the repository, rather any issue numbers should be referenced in the PR description.

Commits are often shared between repositories, so referencing a specific repository's github-specific numbers in commits causes problems where it tags the wrong issues/PRs and otherwise generally causes confusion.

[davecgh]

Code wise this looks fine. However, as mentioned above, the commit title will need to modified per the above and the PR updated with it before it can be merged.

[davecgh]

For reference, I used squash to correct the commit title since the original author never followed up.

[energiplatform]

thanks