Improved main menu.
Aesthetic update to modern standards (bigger fonts, more white space, few icons)
cache settings
mini profiler initializer
Configurable logo
settings cache symbols instead of strings for keys
configurable HTML instructions with WYSIWYG editor and other minor improvements
logged in as in upper right corner
minor UX fixes
invoice model
Configuration.cache implemented in a way that does not need the code to be changed
invoice model improvements and tests
minor general fixes
PDF receipt generation
send invoice via email + tests
added .gitignore in invoices/
css fix to credit card form
invoice procedure improvements + updated docs
minor fixes
minor improvement to formatting of notification