Bug 22581: Add new system preferences

Bug 22581: Add new system preferences

This patch adds 2 new system preferences:
1. OPACShowMusicalInscripts - to toggle musical inscripts to appear in opac's detail page
2. OPACPlayMusicalInscripts - to toggle musical inscripts to be transformed and payed in midi. Depends on OPACShowMusicalInscripts to be enabled.

To test:
1. apply this patch
2. perl installer/data/mysql/updatedatabase.pl
3. search for this new preferences in admin module
SUCCESS => they appear in OPAC section.
4. sign off

Sponsored-by: Biblioteca Provincial Fr. Mamerto Esquiú (Provincia Franciscana de la Asunción)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>