Rename from IPDB to DB - step two
Final step of rename from IPDB to DB

Also fixed bad repo info the dist.ini files while I was in there.
Add metadata debugging output and show it when the reader is in debug mode
Output IP address bit string in debugging, not integer value
Move metadata reading to a role so it can be shared with the database verifier
Make a separate NodeReader role for the benefit of the verifier code
Add 16 bytes of NULLs as a separator between the search tree & data section

Empty records are now indicated by a value == number of nodes

Taken together, these changes make it possible for a verifier to reliably
distinguish between the search tree and data section.

Previously, it would have been possible for the search tree to contain an
arbitrarily long string of NULLs (X empty records), so there was no unique
value that could distinguish the search tree from the data sction.
Work in progress on the MaxMind DB verifier
Remove unused DEBUG constant
Remove temporary debugging hack in verifier
Check that we don't have any "left over" pointers after walking the data section
No need for $DataSectionStartMarkerSize variable in Reader role
Fix "MaxMind, Inc.." typo in LICENSE files
Lots of changes to the verifier

This fixes some bugs in the verification and adds more checks. It now checks
to see that every "top level" structure in the entire data section has a
corresponding pointer from the search tree, and vice versa (every data section
pointer corresponds to a top level item).
Fix dist.ini files to make it possible to run dzil build
Don't include MaxMind::DB::Writer modules in prereqs
Add support for boolean types in MaxMind reader & writer
Make reader->_reader handle metadata so we can get the metadata object easily
Add a script to dump a database's metadata
Change double to use IEEE754 and add a float type