Added footnote linking to IVOA Documents
Added space between citation (Deelman 2005) and workflows
s/This/This understanding/ in executable graph paragraph
s/key in order to/vital to/ after SEPUBLICA2012 reference
allows providing free-text > allows the software designer to add free-text
s/not well solved/unresolved/
Corrected links to STILTS syntax for LaTeX

~mbt > \~mbt
Another correction for taking into account that \~m puts a tilde on top of m
Updated PDF