CardTest: Cluster chaining from FAT
CardTest: Cluster chaining from FAT

Resolve cluster chain from FAT table before reading individual
sectors. Tested ok with Utils/SerialTest.gt1 (20K)

Moved loader to high memory in 32K address space.

No use yet for any other programs of 8KB or more, because those all
load into zero page and/or relatively high memory as well.

kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom,kervinck/gigatron-rom