Several examples for ESP8266 wifi modules with 'ai-thinker.com' AT command firmware version 0.9.2.4

###Notes

• Actual esp8266 library is under common folder and it is almost hardware indipendent.
• Key idea for the library is: you have a relatively large ring buffer for storing the uart messages coming from module for later analysis. Therefore you can't miss any messages up to certain degree.
• Hardware dependent part of the library is esp8266_hal.c file and it can be found under example folders.
• esp8266_hal_rebootSystem() method is used to reboot the whole system in case anything fails. It is utterly useful for fault tolerance. For example; wifi might go offline and transmisson error happens. In order to maintain functionality, system reboots itself and tries to re-connect to the wifi network and all. This may not be desired in every situation but it is better than nothing.