* Don't set SDFAT_FILE_TYPE, default is OK
Fixes#2772
No need to set SDFAT_FILE_TYPE=3 as that is the defaulr value with upstream
SdFat. Remove it from platform.txt and platform.io build.
* Codespell got all techy
Fixes#1356
Mac and Windows have case-insensitive filesystems, so the will find
the internal (all-lowercase) "btstack.h" and not the library's "BTstack.h",
causing compilation errors.
Rename the library and header to avoid the issue.