rename function and update calls.

implement compareLink function.

implement removeTags function

update logger levels in calls

implement log() function.

* Rewrite:
- stopped using deprecated NETWORK_* constants, now Protocol::* should be used
- still left them intact for slow/lazy developers ...

* Removed deprecated NETWORK_* constants as per code reviewer's request.

* Rewrite:
- moved all CONTACT_* constants from boot.php to Contact class

* CR request:
- renamed Contact::CONTACT_IS_* -> Contact::* ;-)

- Remove unused use statement
- Remove superfluous use statements (classes in the same namespace)
- Add missing use statements

Issue #3878

Issue #3878

- Add `use Friendica\App;` wherever needed

Signed-off-by: Roland Häder <roland@mxchange.org>

---------------------
function bla (App &$a) {
	$a->bla = 'stuff';
}
---------------------

Signed-off-by: Roland Häder <roland@mxchange.org>

- space between "if" and brace
- curly braces on conditional blocks

Signed-off-by: Roland Häder <roland@mxchange.org>

Conflicts:
	include/lock.php

- space between "if" and brace
- curly braces on conditional blocks

Signed-off-by: Roland Häder <roland@mxchange.org>

Conflicts:
	include/lock.php

- space between "if" and brace
- curly braces on conditional blocks

Signed-off-by: Roland Häder <roland@mxchange.org>

- count() returns very different results and never a boolean (not even false on
  error condition).
- therefore you should NOT use it in boolean expressions. This still *can* be
  done in PHP because of its lazyness. But it is discouraged if it comes to
  more clean code.

Signed-off-by: Roland Häder <roland@mxchange.org>

This reverts commit db949bb802.

Only define functions if they have not been defined before, e.g. in themes. This makes it possible to override parts of a module and still use the other functions.

NOTE: I didn't add "AND account_removed = 0" to facebook.php because I don't
have a clone of the addons repository. Please someone do that for me. Thanks.

Please check carefully. I tested locally on my server, but not with other
servers.