Various fixes

[mitar]

I do not expect this PR to be merged, but I am making it for visibility. We had to use this tool to convert some old Paradox data to a new format and found this tool good, but not perfect and had to fix it in few places to convert it without data loss.

• Support on 64 bit systems.
• It does not try to specially handle encoded characters, but leaves this to the user to post-process. We had some tables in one 8-bit code table and some tables in another. Which code table is used is obtainable from Paradox metadata (using pxinfo tool from this repository) and then we just post-process it in Python and convert to unicode. Easier than putting this into pxtools.
• There was a bug which prevented some blobs from being correctly read. Only first 10 bytes were. Fixed.

[ustramooner]

wow, this repo is a blast from the past :)
nice stuff. thanks

[mitar]

Thank you for it! It was a life saver for migrating old data to a new system!