Initial commit of Fabric fabfile
Added small local database to reduce runtime and network traffic

Since CPU count and clock speed don't usually change very often,
it makes little sense to query each host for those values every
time the program is run.

A host will be queried only if it's not yet in the databse, or if
its database entry is older than some threshold (currently set to
one week).

I added a little code to read and write a plain text database file
containing YAML. This enables the load check to run faster. In my
setup, where it interacts with 24 remote machines, this change has
brought ~20 second run times down to ~10 seconds.