Bug 24883: Command line utility to load yaml files

Bug 24883: Command line utility to load yaml files

This patch adds a command line utility to load
yaml files.

To test:
1) Apply the patch
2) Try loading a file, e.g. sample notices
 a) mysql -e "delete from letter"
 b) misc/load_yaml.pl -f installer/data/mysql/en/mandatory/sample_notices.yml
3) Try loading a file with a syntax error,
   edit previous file adding ':' at the end of a field without quotes
   then load again

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>