Since IRAM is such a precious resource on the ESP8266, dump out its size
(and all other segments) at the end of the build process.
Ex:
Executable segment sizes:
IROM : 338932
IRAM : 27263
DATA : 1476
RODATA : 2896
BSS : 30304
Sketch uses 370567 bytes (35%) of program storage space. Maximum is 1044464 bytes.
Global variables use 34676 bytes (42%) of dynamic memory, leaving 47244 bytes for local variables. Maximum is 81920 bytes.
