Shorten Dashdash post, replace iPhone w/ Lifeline

Note the new top-level "other" folder for things that should be in version control, but that aren't part of the blog itself.
Minor edits, including improved video embed size
Incorporate fantastic suggestions from @kvanscha – thanks!

Google doc with comments/suggestions: https://docs.google.com/document/d/1iunW3pqVZ0zZSZgBygtNYUNQHUpEhmuRIP2w1Wiqh_8/edit
Clean up Lifeline Excercise diagram
Make final edits to the Dashdash post & publish it
Un-italicize <em>'s in blurbs in item infos
Replace link to archive.org w/ blog.stevecheney.com
Highlight URL in Ver.se screenshot