Sentence case titles remove gerunds (part 1)

[samrrichards]

This is the first PR for #231, which makes the requisite changes to files in the "Auxiliary Knowledge and Utilities" and "Client and Developer Interfaces" section.

I figured I'd open a smaller PR before making the changes more globally because:

• A lot of files ended up being touched, which might make larger PRs difficult to review. (Let me know if you have capacity to look at larger PR's, though!)
• I wanted to check in to make sure that the type of changes I'm making are in line with what's needed before applying them to the rest of the project.

Let me know what you think - hopefully I'll be able to contribute more similar changes soon!