tried your code and get following errors:
ESP_WebConfig_Master.ino: In lambda function:
ESP_WebConfig_Master:163: error: 'stopAll' is not a member of 'WiFiUDP'
ESP_WebConfig_Master:165: error: 'class EspClass' has no member named 'getFreeSketchSpace'
ESP_WebConfig_Master:166: error: 'Update' was not declared in this scope
ESP_WebConfig_Master:170: error: 'Update' was not declared in this scope
ESP_WebConfig_Master:174: error: 'Update' was not declared in this scope
'stopAll' is not a member of 'WiFiUDP'
What Arduino IDE Version did you use?
I tried Arduino 1.6.1 and 1.6.5 same result. What is going wrong. I even reinstalled esp8266 version 1.6.4.
The first version of proteus74 compiles perfect with 1.6.1 and works. Not very reliable but works if you just let it run.