Fix `org-insert-heading' before first headline

* lisp/org.el (org-insert-heading): Fix error when inserting
  a headline before first headline, with point not at bol.  Remove
  source block check for consistency with behavior after first
  headline.  Tiny fix to docstring.

* testing/lisp/test-org.el (test-org/meta-return): Remove unnecessary
  test (not testing specifications).
(test-org/insert-heading): New test.
Merge branch 'maint'

Conflicts:
	lisp/org.el
	testing/lisp/test-org.el
Backport change in r117298 from Emacs trunk
org.el (org-overview): Don't call `recenter'

* org.el (org-overview): Don't call `recenter'.

Thanks to Nicolas Richard for suggesting this.
org.el (org-insert-heading): Be more consistent in respecting content

* org.el (org-insert-heading): With one universal prefix
argument or `org-insert-heading-respect-content' set to `t',
always respect the content, i.e. don't insert a list item and
don't convert normal lines into headings.  Update docstring.
(org-insert-heading-respect-content): Remove unused arg.
(org-insert-todo-heading-respect-content): Don't use
`org-insert-todo-heading-respect-content', use the second
argument of `org-insert-todo-heading' instead.

* org-mobile.el (org-mobile-edit): Use only one arg.

Thanks to Bernt Hansen for reporting this.
Merge branch 'maint'

Conflicts:
	lisp/org.el
ob-exp: Fix export error

* lisp/ob-exp.el (org-babel-exp-process-buffer): Fix error when
  `org-confirm-babel-evaluate' is set to a function.

Thanks to Charles C. Berry for reporting it.
http://permalink.gmane.org/gmane.emacs.orgmode/87403
Small optimization

* lisp/org.el (org-adaptive-fill-function): Do not compute fill prefix
  if point is at a heading or an inlinetask.  Also change "? " into
  "?\s" for better code readability.
Prefer `set-window-start' over `recenter' in some places.

* org-agenda.el (org-agenda-show-1):
* org-table.el (org-table-show-reference):
* org.el (org-fix-ellipsis-at-bol)
(org-first-headline-recenter): Use `set-window-start' instead
of `recenter'.

* org-agenda.el (org-recenter-heading): Delete.
Merge branch 'maint'
org-agenda.el: Fix bug when redoing sticky agendas with log mode and/or clockreport mode on

* org-agenda.el (org-agenda-mode): Let `org-agenda-redo' DTRT
when agenda are sticky.
(org-agenda-tag-filter-while-redo): Delete.
(org-agenda-list, org-agenda-redo, org-agenda-filter-by-tag):
Remove unused code.
(org-agenda-clockreport-mode, org-agenda-set-mode-name): Don't
consider tag filters.

Thanks to Bernt Hansen for reporting this.
Merge branch 'maint'

Conflicts:
	lisp/org-agenda.el
Fix 30220ff
Merge branch 'maint'
customizable parameter to raise more noweb errors

* lisp/ob-core.el (org-babel-noweb-error-all-langs): Raise noweb
  errors regardless of language.
  (org-babel-expand-noweb-references): Make use of the new
  `org-babel-noweb-error-all-langs' variable.
Create org-gnus links from original group, not virtual

* lisp/org-gnus.el (org-gnus-store-link): When in a virtual group,
use the real group instead.
fix semi-backend bug in org-mime

* contrib/lisp/org-mime.el (org-mime-multipart): Fix bug in use of the
  semi org-mime-library when converting emails to HTML.
Merge branch 'maint'
Minor code clean-up

Thanks to Thorsten for this.
org-gnus.el: silent compiler