Added a TOC to examples/README, resorted examples.
Added a TOC to examples/README, resorted examples.

Signed-off-by: Carlos Boneti <af434c6ee35166d4e475365d9b9b7b48485a68af@google.com>

GoogleCloudPlatform/hpc-toolkit,GoogleCloudPlatform/hpc-toolkit,GoogleCloudPlatform/hpc-toolkit,GoogleCloudPlatform/hpc-toolkit