-add style to all the pages
-modify the look of the view "caisse"
-we have to filter the category by Jquery in order to keep the focus on
a button category when it has been clicked
-the button edit doesn't work anymore in product, I have to find why
-add the TVA as a model in our project
-develop a function to get the dummy reference to a product but I don't
see how to call it from listproduct.html
debug edit a product
add ref to product
modify caisse.html
*Add googleapi fonts to improve the look of the fonts
*modify the view facture and listproduct
*resolve some issues with the menu
*add a statistics page to the menu with an example of graph that we can
*adapt to our project.
Merge branch 'lucien'

Conflicts:
	ProjAppliWeb/src/main/java/m2/project/controller/ProductController.java
	ProjAppliWeb/src/main/java/m2/project/model/Category.java
	ProjAppliWeb/src/main/java/m2/project/model/Facture.java
	ProjAppliWeb/src/main/java/m2/project/model/Product.java
	ProjAppliWeb/src/main/resources/public/ThemeTemplate/assets/css/main.css
	ProjAppliWeb/src/main/resources/templates/customer/customerslist.html
	ProjAppliWeb/src/main/resources/templates/employee/employeeslist.html
	ProjAppliWeb/src/main/resources/templates/facture/facture.html
	ProjAppliWeb/src/main/resources/templates/index.html
	ProjAppliWeb/src/main/resources/templates/product/caisse.html
	ProjAppliWeb/src/main/resources/templates/product/listproduct.html