add CR+LF line end to serial_system class for ESP300.
modified:   Makefile: upgrade to version v0.3.5 .
modified:   VERSION: version v0.3.5 .
modified:   serial.h: add CR+LF append to value send in writes function.
modified:   serial_get.help.output: auto updated.
modified:   serial_put.help.output: auto updated.