FAT and NTFS should not pass as MBR by signatures

[kgermanov]

If pass NTFS/FAT volume instead of MBR disk, that wrong detected as MBR, because they are have same sector signatures. Need filter them.

[codecov]

Codecov Report

Merging #5 (2ae6d18) into main (6f8f36a) will decrease coverage by 24.30%.
The diff coverage is 0.00%.

❗ Current head 2ae6d18 differs from pull request most recent head 2cecd9a. Consider uploading reports for the commit 2cecd9a to get more accurate results

@@             Coverage Diff             @@
##             main       #5       +/-   ##
===========================================
- Coverage   55.21%   30.91%   -24.31%     
===========================================
  Files          16       15        -1     
  Lines        1878     1695      -183     
===========================================
- Hits         1037      524      -513     
- Misses        841     1171      +330     

Impacted Files	Coverage Δ
libvsmbr/libvsmbr_boot_record.c	80.55% <ø> (-13.09%)	⬇️
libvsmbr/libvsmbr_chs_address.c	85.96% <ø> (-14.04%)	⬇️
libvsmbr/libvsmbr_error.c	100.00% <ø> (ø)
libvsmbr/libvsmbr_io_handle.c	72.97% <ø> (-27.03%)	⬇️
libvsmbr/libvsmbr_notify.c	76.47% <ø> (ø)
libvsmbr/libvsmbr_partition.c	18.25% <ø> (-66.28%)	⬇️
libvsmbr/libvsmbr_partition_entry.c	80.95% <ø> (-19.05%)	⬇️
libvsmbr/libvsmbr_partition_values.c	85.18% <ø> (-14.82%)	⬇️
libvsmbr/libvsmbr_section_values.c	70.37% <ø> (-29.63%)	⬇️
libvsmbr/libvsmbr_sector_data.c	52.56% <ø> (-19.94%)	⬇️
... and 18 more

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[joachimmetz]

Thx for the suggested changes. Note that per README this project is experimental, I'll have a look when time permits.