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

Happy it is being useful :)

Just a couple of remarks:

• No need for two different linker scripts (app1 and app2). By definition in this mode both images should be identical (which is indeed a great advantage), so we only need to generate one, and if we want to keep two for consisntency, I would point both linker scripts to the same file.
  
• We need to check the upper limit. In the "jswrap esp8266 network.c" file you pointed before as having a hardcoded flash address, I see it is pointing to the last page, looks like) so we may need to adjust the linker script to allow for one page less size, and of course adding 1Mb to the flash address if we are in image 2 (in runtime, getting the base flash address from the corresponding sdk os_* function)