Updated atlas.json
Adding callout images.
Putting image alt text that contains commas in quotes.

Conflicts:
	book/01-introduction/sections/basics.asc
Fixing duplicate id.
Merge pull request #201 from progit/epub-fix

Epub Fixes
difftool reference?
Merge branch 'epub-fix'
try just changing it
Fix typo
Merge pull request #202 from harupong/ch06-typo-fix

Fix one typo
Use always "SHA-1" instead of "SHA"

Signed-off-by: Thomas Ackermann <th.acker@arcor.de>
Remove dangling full stop

Signed-off-by: Thomas Ackermann <th.acker@arcor.de>