org-e-ascii: Fix justification for lines looking like a fill-prefix

* contrib/lisp/org-e-ascii.el (org-e-ascii--justify-string): Fill
  justification for lines looking-like a fill-prefix.
ob-exp: Fix code indentation after src block evaluation

* lisp/ob-exp.el (org-export-blocks-preprocess): Do not use
  `indent-code-rigidly' as it doesn't indent contents of strings.
org-export: Fix smart quote bug with footnote definitions in ascii back-end

* contrib/lisp/org-export.el (org-export-activate-smart-quotes): Fix
  error when exporting a footnote definition.
Merge remote-tracking branch 'refs/remotes/upstream/master'
Add caching mecanism

* contrib/lisp/org-contacts.el: Add a caching mecanism around
  `org-contacts-filter'.