add TDK from Nvidia

Signed-off-by: Fotis Georgatos <fotis.georgatos@uni.lu>
turn modextrapaths into lists & also populate MANPATH

Signed-off-by: Fotis Georgatos <fotis.georgatos@uni.lu>
this fixes hpcugent/easybuild-easyblocks#189

Signed-off-by: Fotis Georgatos <fotis.georgatos@uni.lu>
Merge pull request #489 from fgeorgatos/contrib_TDK

add Tesla Deployment Kit from Nvidia