Known bugs:

Sep 26 2015:

    1. [DONE] MSBO and related entities:
        The MSBO object is buggy; although models are largely preserved and rendered as
        expected, some features are damaged and in FreeCAD they can be seen as points
        scattered in space. The logic must be checked to ensure a faithful copy of the
        data.

Sep 29 2016:

    Items to check:

    1. [DONE] FormatDEInt: what does the specification say about integers in the Directory Entry
    section? If a positive integer may have 8 characters, is any extra code needed to
    guard the formatting of the DE Line number?

        NOTE: no explicit limit is set, but since Section Line Numbers are only 7 characters
        we are limited to a maximum of 9 999 999 PE lines. Since the fields are only 8
        characters, the implicit limits for all other values are -9 999 999 to +99 999 999.
        The range of the negative values is consistent with a negative value being used to
        represent a DE or PE line number.

        DE formatter (iges_entity.cpp) already guards against Line Numbers with more than
        7 digits. AddPDItem() in iges_io.cpp was updated to guard against line number
        overflows.



    2. Numeric formatting in the Parameter Section: the specification states that the
    end of parameter or end of record must appear on the same line as a number; this
    may require blank padding of some PE lines and possibly some modification of the
    numeric formatters to ensure that numbers end before Column 71 (end marker goes in C71).
    Check:
        a. [OK] the numeric output formatters
        b. [OK] the parser (must skip blank padding)

    3. Extending support for other Entity Types:
        Use model 10029449-001LF.igs as input to provide support for Entity Type 406.
