New songbook minor changes
Change the default "back to songbook URL"
Revert "Customize the container tag of the fields in all forms"

This reverts commit 62c5539722c642eafe9473fc80f50da069de8cb3.
minor input border-color change
Fix HTML in login page
Submit buttons styling
.button-link style moved to form.less
Form further styling
Add screen sizes variables (from bootstrap)
Form layout fix
All form submit button MUST be inside a <p> tag
Captcha styling
Login form styling
Form design fix
Delete songbook form minor changes
Login form: remove useless div insertion when no error
Form style : select
Book icon with transparent background
Unify songbook top-menu
Useless links in public songbook list