Capture: Allow more control over inserted whitespace in capture templates
* lisp/org-capture.el (org-capture-place-entry): Place captured entry
immediately after last subheading of target, instead of just before
next heading at same level as target.
* lisp/org-capture.el (org-capture-templates): Document new capture
template properties.
* lisp/org-capture.el (org-capture-place-entry,
org-capture-empty-lines-before): Make new :empty-lines-before property
override :empty-lines when inserting empty lines before captured
captured entry.
* lisp/org-capture.el (org-capture-finalize,
org-capture-empty-lines-after): Make new :empty-lines-after property
override :empty-lines when inserting empty lines after captured
captured entry.