- Add missing documentation for options and environment variables
- Rearrange definition and documentation of 'Options', 'Variables'
and 'Aliases' in a consistent order
The 'history' command is the same as 'fc -l', using a '.' as the first
parameter will get the history from the first command starting with a '.'.
Instead a '0' should be used, meaning that the history is taken from the very
first entry in the history.
