This is admittedly a very nitpicky change.
For most of the changes, I went through the various Markdown files and added
language names to the source blocks for better syntax highlighting on GitHub. It
also makes it easier to copy and paste commands without copying the leading `$`.
I avoided changing anything in `third_party`.
Additionally, I added some instructions for compiling the Android samples on the
command line and fixed some typos.
58017a0e6a