Added sf\3tshell platform with support for building beagle textshell+fshell ROMs.
As part of that:
* Added baserom command and tweaked it to be more friendly with SF baselines.
* Lots of build fixes
Also cd now makes sure the current working directory matches the file system with respect to case.
---------------------------- Test N1 ------------------------------
1:abc
2:def
---------------------------- Test N2 ------------------------------
1:abc
def
2:ghi
jkl---------------------------- Test N3 ------------------------------
2:def
3:
ghi
jkl---------------------------- Test N4 ------------------------------
2:ghi
jkl---------------------------- Test N5 ------------------------------
1:abc
2:def
3:ghi
4:jkl---------------------------- Test N6 ------------------------------
1:abc
2:def
3:ghi
4:jkl