Arduino SIM800L v0.2.1

• Fix compatibility with Arduino 1.8.12 and AVR Boards 1.8.2
• Pass lint

Arduino SIM800L v0.2

• FTP PUT method, in order to upload binary data to a remote server. I tried to upload images up to 1MB with success. It is interesting if you have a camera like OV5642, OV5640 or Arducam, using them.
• Memory improvements, by allocating memory from PROGMEM when necessary instead of filling the heap of data that is not always used.
• Example about how to fetch data in batches from the SD card in order to upload to a remote server.
• Example about how to take a photo with Arducam, save it to SD card and upload to remote FTP server.
• Refactor to match the 1.5 Arduino IDE specification

Arduino SIM800L v0.1

• Main http actions used to develop an small remote clients
• Main features to communicate with the SIM800L module using the AT commands