Added local scoping of el variable in indispensable.sh::make_dir
Added get_age_of_file_in_seconds_since_epoch

- added create_lock and remove_lock methods

- added global lock_file variable.
Created module for date and time related functions.

- moved time function from indispensable to date.sh.
Commented out tests.
Improved watch-websites command.

- now prints the HTTP status code

- uses curl instead of wget, somewhat simpler, less code.

- now loads other moria libraries relatively.

- Added documentation header.