Add long_schedule doc, add long_schedule example

To complement https://github.com/basho/riak_sysmon/pull/16 and
https://github.com/basho/riak_sysmon/pull/11.
fix small syntax errors
make runtime health doc conform to 72 char rule
add long_schedule config to configs table
Merge pull request #1359 from basho/features/slf/long_schedule

Add long_schedule doc, add long_schedule example