Until now the main makefiles of Nitro Engine have been the ones of
devkitPro, forcing users to go through extra steps to build everything
under BlocksDS.
Now, the easy makefiles are the BlocksDS ones, and additional notes have
been added to warn about the limitations of devkitPro:
- No GRF support in libnds.
- NitroFS doesn't work in melonDS.
Using global variables is generally discouraged. Now that NE_ProcessArg()
and NE_ProcessDualArg() exist, it's better to show how to use them instead
of NE_Process() and NE_ProcessDual() while using global variables.
Also, switch from "int main(void)" to "int main(int argc, char *argv[])".
