Changed e-mail address for George

Using new e-mail will cause the avatar to appear in e-mails. At least
it should.
Improved the headings

Changed colour of H4 and replaced font with increased size with
headings of size 4
Fixed #47

Reduce the line-height of messages and improve overall looks
Fixed #41

Add an information about empty list
Fixed #40

Make Alerts react on mouse hover
Fixed #46

Improve the look of the footer