Uplift LMDBJava to use LMDB 1.0.1 #295

LMDB 1.0.1 has recently been released
https://lists.openldap.org/hyperkitty/list/[email protected]/thread/JOHKNPZ5DURYFMCYXCYRKVQQLJUMNBAP/

Here are the upgrade notes for LMDB v1.x
http://www.lmdb.tech/doc/upgrading.html

Given that LMDB v1.x file format is NOT backwards compatible, and thus will NOT read a file created by LMDB v0.9.x, users of LMDBJava will have to put their own migration plans in place to dump+load or re-create their existing envs.

You must use v0.9 #mdb_dump to export your old DBs, and import with v1.0 #mdb_load if you want to migrate your existing data to use LMDB 1.0. There is no support in LMDB 1.0 for operating directly on v0.9 DB files.

This may be useful for performing migrations - https://github.com/PowerDNS/lmdb-converter

Probably the best approach for dealing with this uplift is as follows:

1. Fix the main outstanding issues:
   • SIGSEGV running tests #279
   • Improve iterator performance and add better stream support #269
2. Uplift any dependencies to their latest non-breaking versions, e.g. jnr-ffi
3. Release LMDBJava as 0.9.x
4. Create a 0.9 branch for supporting future 0.9.x fixes.
5. Uplift LMDB binaries to v1.0.1
6. Implement wrappers for the the new LMDB methods (e.g. mdb_txn_prepare()) and add tests.
7. Release LMDBJava as v1.0.x
8. Document the options for upgrading from LMDBJava v0.9.x => 1.x

An alternative is do the fixes and release LMDBJava as 1.0.x, Then the uplift of LMDB to v1.0.1 goes into LMDBJava 2.0.x.

It may also be beneficial for the LMDBJava version numbering to include the LMDB ver in it, e.g. 0.9.4-lmdb-0.9.33-5. This makes it clear what LMDB version a version of LMDBJava is targetting, particularly for those using their own provided binaries.