add script to compress firmware before ota upload (#1065)

* add script to compress firmware before ota upload

* add examples for OTA flashing/updating Sonoff RF Bridge

- use compress script to save space uploading firmware
- use "board_build.ldscript = eagle.flash.1m64.ld" to free some additional space for OTA flashing.

platformio.ini

@@ -195,6 +195,8 @@ build_flags =
   '-DGateway_Name="OpenMQTTGateway_SRFB"'
   '-UMQTTsetMQTT' ;We remove this function to have sufficient FLASH available for OTA, you should also use ESPWifiManualSetup to save flash memory and have OTA working
 board_build.flash_mode = dout
+board_build.ldscript = eagle.flash.1m64.ld ;this frees more space for firmware uplad via OTA.
+;extra_scripts = scripts/compressFirmware.py ;uncomment this to compress the firmware. This helps updating e.g. Sonoff RF Bridge via OTA flash by saving space for the uploaded firmware.
 
 [env:esp32dev-all-test]
 platform = ${com.esp32_platform}
@@ -1071,3 +1073,5 @@ build_flags =
 	'-DINPUT_GPIO=0'
 	'-DGateway_Name="OpenMQTTGateway_SRFB_Direct"'
 board_build.flash_mode = dout
+board_build.ldscript = eagle.flash.1m64.ld ;this frees more space for firmware uplad via OTA.
+;extra_scripts = scripts/compressFirmware.py ;uncomment this to compress the firmware. This helps updating e.g. Sonoff RF Bridge via OTA flash by saving space for the uploaded firmware.