[#150] Mouse graphic isn’t used, so removing.

Also updating screenshot to present a more accurate representation of
Herbert’s true self.
Project sections and order changed
Ghostbusters resources added
Merge pull request #151 from andylolz/150-herbert

[#150] Mouse graphic isn’t used, so removing.
Added some {.new-page} tags in readiness for auto PDF rendering
Paint Box: fixed Scratch blocks in Step 4
Scratch cards moved from 'Frantic Felix' to 'Sound Machine' project
Rename Table Football lesson; Beautify PDF