Proposed, and implemented, some enhancements (1Mb + 1Mb firmware, resizable jsvars size, ...)

Hi @MaBe, 1MB for save code won't work, as far as I have seen in the code. The main reason is that saved code must be first allocated somewhere in RAM, and we do not have so much RAM :)
Also, when we already have saved code in flash, and we try to save state later, the whole code in flash will try to go to the stack (alloca) temporarily ro reflash, which for sure is not good.
In my code you will find an implementation of alloca that will check if we have enough stack and at least return NULL if not enough room, instead of overflowing.
Regarding RESIZABLE_JSVARS, the code is already there for Linux, I did not reinvent the wheel :) The idea is to leave as much heap free as possible when not needed for JsVars (better encryption, more connections, etc), and allow it to grow on demand. Of course there is some work to be done, to make sure we always leave a minimum, but it is just an "if" in the provided malloc function, and a check for NULL in where the code calls malloc (I think I did not see this check in the LINUX code, but it is quite straight forward)