Fix exception handlers (thanks @fincs)

[stage1] Add exception handlers... which somehow don't work?

Fusee use CAR reboot for fatal errors

Remove packed when not needed

Don't check for panics in stage2

wtf pmc reboot doesn't fully work -- display doesn't reinitialize

Introduce fatal_error

fusee: correct computation of tuning block size

fusee: begin adding support for MMC HS modes

fusee: SD: implement tuning, allowing for all SD UHS-I speed

fusee: SD driver: implement everything necessary for UHS except tuning

fusee: correct constants in CAR

fusee: handle SDMMC speeds sanely

Add custom panic driver

Make struct tegra_pmc not packed

Actually don't use memcpy in sdmmc

Sync sdmmc changes between stage1 and 2

Use memcpy instead of raw casts in sdmmc.c

Revamp all the Makefiles (thanks @fincs @WinterMute) ...

... dependencies are now properly handled (e.g. header changes, etc.)

fusee sdmmc: don't time out on long reads

Exosphere: Fix remaining crt0 bugs, we now make it to pk2ldr.

Exosphere: Fix bug, we now make it past MMU enable.

Exosphere: Copy initial data image to DRAM for coldboot init.

Exosphere: Fix relocation bug (warmboot relocs currently broken in edge case)

[stage2] Add more debugging printfs to package2.c, etc.

Fix nxboot mkey rev misconception

Refactor nxboot package2 reading, work around sdmmc issue, other changes

[stage2] Fix some FS bugs

[exosphere] Fix bug in package2.c

Fix bug in fusee: package2.c, etc.