Add and fix copyright notices for better GPL compliance (thanks @naehrwert and @CTCaer).

fusee: Complete re-write of the hardware initialization code: ...

- Updated code to match hekate's;
- Improved nxboot (now boots firmwares 2.x successfully);
- Temporarily disabled built-in boot system module support;
- Fixed multiple bugs.

Fusee: Deployed new SDMMC driver in fusee-secondary. All stages boot now. ...

Fusee: Fixed wrong argument in se.c function.
Fusee: Improved timers.

Make sdmmc autocalibration follow TRM procedure ...

Sleep for 1 us, not 1 ms.
Timeout after 10 ms, set driver strength code values according to TRM.

Fix typo (mS) - time is in milliseconds, not milliSiemens.

Merge SD stuff into fusee-secondary. Switch diskio to single-sector reads temporarily