crontab basics

How to list, create, edit and delete cron jobs.  Also describes crontab fields.
Added output of crontab command to file
Changed markdown syntax
cat basics

Includes: to standard output, to another file, and combining files
Fixed typo.  I think it was supposed to be "extracting data", not "estracting data"
Monospaced commands and file paths per @avleen's suggestion
Removed double spaces between sentences and limited lines to 80 characters.
Bit of a hodge-podge commit.  Made changes per all but one of the remaining suggestions.
Write some basic text about the RFCs.

This still needs some more detail. It does provide a basic description
of the RFCs and the process involved in their publication and
development. In addition, it provides a list of important RFCs, those
that aren't specific to a protocol but nonetheless generally useful /
important.
Link the RFC documents with :rfc:`NUMBER`.

Thanks, Mike!
Various and sundry small cleanups.

Trailing whitespace removed, reworded a few things to be cleaner or less
verbose.
Clean up bullet formatting.

Add some indents to make things neater. Thanks, Mike!
Merge pull request #48 from apeiron/topic/apeiron/todo-intro-to-rfcs

Introduce the RFCs
Added short explanation of fields that start with 0 or 1.
Merge pull request #28 from bmacri/master

crontab basics
cron 101: style update
cron 101: fields to table
cron 101: indent table
fixing indentations & long lines
careers: style edits, heading changes