2.2.0-master_20180402

This is based on Espressif NON-OS SDK 2.2. plus its patches, #2269

New modules

• WiFi monitor, #2204
• Bloom filter, #2176
• BME680, #2151
• WS2812 effects library, #2215

Noteworthy enhancements

• Deprecated init function was removed from I2C-based modules, #2276
• mbedTLS upgraded to 2.7.0, #2267
• New functions wifi.getcountry() and wifi.setcountry(), #2330
• SPIFFS upgraded, #2172
• LuaOTA provisioning system, #2060

Bug fixes

Many

Check the 2.2 milestone for all details: https://github.com/nodemcu/nodemcu-firmware/milestone/8?closed=1