What is Energia from cpp perspective?

I am sorry if this has been answered elsewhere. 

My understanding is that Energia is a combination of the following:

1) an IDE 

2) a run-time library (digitalWrite, Serial, etc.)

4) a directory convention

5) a simple preprocessor that 

    5.1. merges files that don't have an extension;

    5.2. adds #include statements (but apparently not all?)

3) a very simple harness that goes like this and turns Energia from a library into a framework:

int main(void)
{
   init();


   setup();


   for (;;) {
      loop();
      if (serialEventRun) serialEventRun();
   }
return 0;
}

4) a coding convention which simplifies C++ programming (while allowing plain C++)

5) a makefile that builds all that.

Did I get that right? And if I did - is it possible to use Energia just as a a run-time library? I.e with my own main().