Add 'inline-only option to org-export-babel-evaluate
* lisp/ob-exp.el (org-export-babel-evaluate): Add a 'inline-only option.
(org-babel-exp-results): Implement 'inline-only for
`org-export-babel-evaluate'.
* doc/org.texi (Exporting code blocks): Document the 'inline-only setting
for `org-export-babel-evaluate'.
This is useful because there is no way for inline results to be stored.
The imagined usecase is that all non-inline source blocks will be
evaluated manually by the user. Inline blocks, however, must be
evaluated during export, or they will be simply deleted by the exporter.