Update paths (1/4)

Update paths in Vol1
Update Paths (2/4)

Update paths in Vol2
Update Paths (3/4)

Update paths in Vol3
relocate Finite Element lab
relocate Spectral labs
Update Paths (4/4)

Update paths in Vol4
cull old labs from volumes
relocate lab
remove first argument

Since labs are no longer classified as algorithms or applications, we
have removed the first argument from \lab command
remove first argument form lab command
remove parts

Add proper appendix (new dependence on appendix package)