2013/11/28 Bugs correction

- Correction of various small bugs
- "Lenght" changed to "Length" in database and codes
2013/12/19 Tables sorting, home page update and bug correction

- Complete change of javascript function for the sorting of tables:
	it now  uses a jQuery plugin: jquery.tablesorter
- Update of the content of the home page (index.php)
- Complete change of the CSS for the horizontal navbar to correct previous bug
- Addition of validation message to prevent empty searches
- Addition of Morton and Gilmour collections in browse_choice.php
- Correction of bugs in the display in display_details.php
- A few other cosmetic changes