Support for third bitmap

[ferch5003]

I am getting this error trying to deserialize a message that contains a 130 field:

error:unmarshalling: deserialize body: failed to unpack field 65: no specification found

Seeing the Bitmap the bit 65 is turned on, but this bit indicates a third bitmap that is active, not a field, so there is not an specification for this case.

[alovak]

@ferch5003 thanks for reporting the issue! I've fixed it here: #255

but I also have to check if it should be fixed for composite fields as well. I hope to fix it for composites today as well.

[alovak]

I checked and Composite works only with fixed bitmaps - so, the #255 is not relevant here.