Simplify command line usage exploiting ELF info

* s/`importGlobalData`/`parseELF`/
* Save the entry point specified in the ELF header, which will be used
  if the user doesn't provide an address.
* Let parse `parseELF` take care of informing libtinycode about what
  has to be mmap'd and where.
* Remove some support scripts used during testing, now no longer
  necessary.
* Various cleanups