address comments by John Slater and Jessica Osorio design-wise
Merge pull request #172 from MichaelKohler/design

address comments by John Slater and Jessica Osorio design-wise
change sign download structure + string + add link
Merge pull request #173 from MichaelKohler/signs

change sign download structure + string + add link
use target blank to open link
Merge pull request #174 from MichaelKohler/target

use target blank to open link
Merge branch 'master' into gh-pages