Add maxmind-db submodule
Make indentation in configure.ac consistent and remove tabs
Add a .indent.pro file
Work in progress on revising the libmaxminddb tests

The goal is to A) use the MaxMind-DB test files and B) improve test coverage
Fix ignore rules for generated files in t/ dir
Update maxmind-db submodule
The BROKEN_PTR issue has been resolved for a while, remove this macro
Rename error codes to be more readable and make them positive numbers
Make MMDB_open return the status code so we can do something useful with failures

This means that MMDB_open now takes a pointer to an MMDB_s struct instead of
allocating one by itself.
Start of new tests with more helpers
Make fdlookup_* function LOCAL

We don't want _users_ of this library to have to know that we have two sets of
lookup functions.
Update to latest MaxMind-DB test data
Add MMDB_lookup public function to lookup an entry from a string address

No need for snprintf_or_bail in test suite since tap.h handle sprintf
internally for test names & diag messages.
Small cleanup to MMDB.h
Run indent on MMDB_Core.c
Can't reorder struct defs in MMDB.h
Check all malloc calls with an assert
Add a helper function to construct the full path to a test database
Start refactoring metadata handling

Metadata is now its own struct. Struct member names match the key names in the
metadata.

Data calculated from the metadata is still part of the MMDB_s struct.

No need for the KEYS macro. You don't need to pass a trailing NULL to a sub
which takes varargs.

Added start of tests for metadata handling.
Remove unneeded MMDB_get_uint function

AFAICT this isn't really useful as a public function