[RFC] Modified Babel call execution and property deprecation

[Nicolas Goaziou <mail@nicolasgoaziou.fr>]

Hello,

I just pushed changes about how Babel calls (including inline calls) are
evaluated. Basically, they are not treated anymore as an Emacs Lisp
variable, but as virtual Babel source blocks, which can then be executed
with `org-babel-execute-src-block'.

I had to tweak a few tests in the process so I guess it will introduce
a few visible changes, in particular in header args as properties. In
any case, please let me know if there's something fishy.

That leads me to the second point. I think it's high time to remove the
deprecated (3 years ago) syntax for header properties, e.g.,

  :PROPERTIES:
  :tangle: no
  :END:

I re-read discussions about it from a couple of years ago, and, AFAICT,
the arguments against it do not hold anymore. So, if you think this
syntax is still useful, i.e., it permits things that the current one
cannot, please speak up.

Regards,

-- 
Nicolas Goaziou                                                0x80A93738