Fixed lint warnings
Changed __init__ signature of Bpb class

Allow to supply filename, offset and length
Bugfix for rawstruct

If only filename is supplied, read all file contents
Ignore pdf files for now
clusters_per_mft is signed byte per Microsoft

http://thestarman.pcministry.com/asm/mbr/NTFSBR.htm

Also added property that returns mft record size in bytes
Changed Bootsector __init__ signature

Allow specifying filename, offset and length
Additional methods for rawstruct
Modified Bpb test to verify mft_record_size
Modified MftTable api
Updated usage doc
Minor change
Fixed lint warning
Added exception to rawstruct constructor
Added tests for MftTable class
Moved mgr load code into __init__
Enhanced MftTable implementation
Changed Bpb __init__ args

Removed length argument, it is always the same
Restructured mft classes

Mft table can now only be initialized with filename and offset, since
on every file retrieval we will need file access, can’t preload all mft
entries beforehand
Minor change
Additional docstrings to MftTable