Rename gravatar_img() more generic to avatar_img().

I would like to extend the Gravatar support to also use Libravatar, a decentralized avatar service.
First step to extract Gravatar from core and put it into its own plugin. Later the Libravatar plugin can be done, too as a plugin.

include/Scrape.php

@@ -446,7 +446,7 @@ function probe_url($url, $mode = PROBE_NORMAL) {
 						$phost = substr($url,strpos($url,'@')+1);
 						$profile = 'http://' . $phost;
 						// fix nick character range
-						$vcard = array('fn' => $name, 'nick' => $name, 'photo' => gravatar_img($url));
+						$vcard = array('fn' => $name, 'nick' => $name, 'photo' => avatar_img($url));
 						$notify = 'smtp ' . random_string();
 						$poll = 'email ' . random_string();
 						$priority = 0;
@@ -655,7 +655,7 @@ function probe_url($url, $mode = PROBE_NORMAL) {
 			}
 
 			if((! $vcard['photo']) && strlen($email))
-				$vcard['photo'] = gravatar_img($email);
+				$vcard['photo'] = avatar_img($email);
 			if($poll === $profile)
 				$lnk = $feed->get_permalink();
 			if(isset($lnk) && strlen($lnk))

include/network.php

@@ -692,13 +692,13 @@ function allowed_email($email) {
 }}
 
 
-if(! function_exists('gravatar_img')) {
-function gravatar_img($email) {
+if(! function_exists('avatar_img')) {
+function avatar_img($email) {
 	$size = 175;
 	$opt = 'identicon';   // psuedo-random geometric pattern if not found
 	$rating = 'pg';
 	$hash = md5(trim(strtolower($email)));
-	
+
 	$url = 'http://www.gravatar.com/avatar/' . $hash . '.jpg' 
 		. '?s=' . $size . '&d=' . $opt . '&r=' . $rating;
 

mod/register.php

@@ -324,7 +324,7 @@ function register_post(&$a) {
 		require_once('include/Photo.php');
 
 		if(($use_gravatar) && (! strlen($photo))) 
-			$photo = gravatar_img($email);
+			$photo = avatar_img($email);
 		$photo_failure = false;
 
 		$filename = basename($photo);
@@ -333,7 +333,7 @@ function register_post(&$a) {
 		if($img->is_valid()) {
 
 			$img->scaleImageSquare(175);
-					
+
 			$hash = photo_new_resource();
 
 			$r = $img->store($newuid, 0, $hash, $filename, t('Profile Photos'), 4 );