Fixes#1164 and thus also #1150, #1149, #1147 and #898.
* Move to latest version of SPIFFS
* Add SPIFFS porting layer for NodeMCU
* Add option to delete output if it doesn't fit
* Change FLASHSIZE to be in bits by default: default 4mb 32mb
* Add SPIFFS_MAX_FILESYSTEM_SIZE override
* Add notes on SPIFFS_FIXED_LOCATION
* Add 1M boundary
* Include the current version of the LICENSE
Marcel Stör
Philip Gladstone