pjproject: align with Asterisk requirements, misc improvements

pjproject: align with Asterisk requirements, misc improvements

- Make "--disable-floating-point" depend on SOFT_FLOAT
- Remove "--disable-ilbc-coder" as configure no longer recognizes it.
- Align args with the ones used by Asterisk (for their bundled pjproject);
  this includes adding "--disable-resample".
- With libresample removed remove the dep from asterisk13 accordingly.
- Note: the disabled items are _not_ used by Asterisk anyway.
- Drop speex dep as pjproject does not link against it the way it is
  configured.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>