set max_connection from code (when less than 4 is needed) (#2326)

* Update ESP8266WiFiAP.cpp

It is not very common but some might require to set the maximum number of clients, from code, to smaller than 4.
in my case i must allow only one client at a time (TESTED WORKING)

* Update ESP8266WiFiAP.h

as discussed in the .cpp (set max connections)

* Update ESP8266WiFiAP.cpp

corrected indentation @70 
add param comment @86

* Update ESP8266WiFiAP.cpp

Author: Stefano-Orsolini

libraries/ESP8266WiFi/src/ESP8266WiFiAP.cpp

@@ -66,6 +66,9 @@ static bool softap_config_equal(const softap_config& lhs, const softap_config& r
     if(lhs.ssid_hidden != rhs.ssid_hidden) {
         return false;
     }
+    if(lhs.max_connection != rhs.max_connection) {
+        return false;
+    }
     return true;
 }
 
@@ -76,12 +79,13 @@ static bool softap_config_equal(const softap_config& lhs, const softap_config& r
 
 /**
  * Set up an access point
- * @param ssid          Pointer to the SSID (max 63 char).
- * @param passphrase    (for WPA2 min 8 char, for open use NULL)
- * @param channel       WiFi channel number, 1 - 13.
- * @param ssid_hidden   Network cloaking (0 = broadcast SSID, 1 = hide SSID)
+ * @param ssid              Pointer to the SSID (max 63 char).
+ * @param passphrase        (for WPA2 min 8 char, for open use NULL)
+ * @param channel           WiFi channel number, 1 - 13.
+ * @param ssid_hidden       Network cloaking (0 = broadcast SSID, 1 = hide SSID)
+ * @param max_connection    Max simultaneous connected clients, 1 - 4.
  */
-bool ESP8266WiFiAPClass::softAP(const char* ssid, const char* passphrase, int channel, int ssid_hidden) {
+bool ESP8266WiFiAPClass::softAP(const char* ssid, const char* passphrase, int channel, int ssid_hidden, int max_connection) {
 
     if(!WiFi.enableAP(true)) {
         // enable AP failed
@@ -108,7 +112,7 @@ bool ESP8266WiFiAPClass::softAP(const char* ssid, const char* passphrase, int ch
     conf.channel = channel;
     conf.ssid_len = strlen(ssid);
     conf.ssid_hidden = ssid_hidden;
-    conf.max_connection = 4;
+    conf.max_connection = max_connection;
     conf.beacon_interval = 100;
 
     if(!passphrase || strlen(passphrase) == 0) {

libraries/ESP8266WiFi/src/ESP8266WiFiAP.h

@@ -36,7 +36,7 @@ class ESP8266WiFiAPClass {
 
     public:
 
-        bool softAP(const char* ssid, const char* passphrase = NULL, int channel = 1, int ssid_hidden = 0);
+        bool softAP(const char* ssid, const char* passphrase = NULL, int channel = 1, int ssid_hidden = 0, int max_connection = 4);
         bool softAPConfig(IPAddress local_ip, IPAddress gateway, IPAddress subnet);
         bool softAPdisconnect(bool wifioff = false);