#18472 Plugin settings now available in javascript as RMPlus.Usability.settings object
#18472 Added setting to switch on/off display of standart redmine ajax preloader gif
#18472 Added few more settings, removed some redundant code from usability.js
#18472 Done all settings in usability.js + option to keep original redmine breadcrumbs in header of project page
#18472 Done all settings in lib patches
Merge branch 'i18472' into development

Conflicts:
	app/views/settings/_usability.html.erb
	assets/stylesheets/usability.css
	config/locales/en.yml
	config/locales/ru.yml