Update IDF to aaf1239 (#1539)

* fix sdmmc config

* Fix warnings in EEPROM

from @Curclamas

* remove leftover TAG in EEPROM

* Initial add of @stickbreaker i2c

* Add log_n

* fix warnings when log is off

* i2c code clean up and reorganization

* add flags to interrupt allocator

* fix sdmmc config

* Fix warnings in EEPROM

from @Curclamas

* remove leftover TAG in EEPROM

* fix errors with latest IDF

* fix debug optimization (#1365)

incorrect optimization for debugging tick markers.

* Fix some missing BT header

* Change BTSerial log calls

* Update BLE lib

* Arduino-ESP32 release management scripted (#1515)

* Calculate an absolute path for a custom partitions table (#1452)

* * Arduino-ESP32 release management scripted
(ready-to-merge)

* * secure env for espressif/arduino-esp32

* * build tests enabled
* gitter webhook enabled

* * gitter room link fixed
* better comment

* * filepaths fixed

* BT Serial adjustments

* * don't run sketch builds & tests for tagged builds

* Return false from WiFi.hostByName() if hostname is not resolved

* Free BT Memory when BT is not used

* WIFI_MODE_NULL is not supported anymore

* Select some key examples to build with PlatformIO to save some time

* Update BLE lib

* Fixed BLE lib

* Major WiFi overhaul

- auto reconnect on connection loss now works
- moved to event groups
- some code clean up and procedure optimizations
- new methods to get a more elaborate system ststus

* Add cmake tests to travis

* Add initial AsyncUDP

* Add NetBIOS lib and fix CMake includes

* Add Initial WebServer

* Fix WebServer and examples

* travis not quiting on build fail

* Try different travis build

* Update IDF to aaf1239

* Fix WPS Example

* fix script permission and add some fail tests to sketch builder

* Add missing space in WiFiClient::write(Stream &stream)

cores/esp32/WString.cpp

@@ -881,3 +881,31 @@ float String::toFloat(void) const
     }
     return 0;
 }
+
+
+unsigned char String::equalsConstantTime(const String &s2) const {
+    // To avoid possible time-based attacks present function
+    // compares given strings in a constant time.
+    if(len != s2.len)
+        return 0;
+    //at this point lengths are the same
+    if(len == 0)
+        return 1;
+    //at this point lenghts are the same and non-zero
+    const char *p1 = buffer;
+    const char *p2 = s2.buffer;
+    unsigned int equalchars = 0;
+    unsigned int diffchars = 0;
+    while(*p1) {
+        if(*p1 == *p2)
+            ++equalchars;
+        else
+            ++diffchars;
+        ++p1;
+        ++p2;
+    }
+    //the following should force a constant time eval of the condition without a compiler "logical shortcut"
+    unsigned char equalcond = (equalchars == len);
+    unsigned char diffcond = (diffchars == 0);
+    return (equalcond & diffcond); //bitwise AND
+}