check_empty for restore was trying to run a git checkout in the current
working directory, instead of in the ~/.notes directory. Fix this issue
note_show uses less to display the contents of the note file.
Fix the following issues in note
1. Always use a combo of lowercase letters, hyphen, underscore and
numbers for the file name. This is taken from the title and uses sed
to translate the uppercase letters to lowercase. Unfortunately,
sed's translation mode doesn't support ranges, so we must use the
full alphabet.
2. Add support for displaying version information.
3. Reformat the help display so it all fits in a single line.
4. Add checking to ensure that at least one argument is passed to note
so that the parse_args routine doesn't barf an error with shift.
5. Remove argument checking in notes_init. It's called only by the init
function, so there's no need to add a flag to control warnings.
nirenjan