v1.0.2
[tests] Add unit tests for arrays, and apply corresponding fixes
[io-engine] rename core_io_engine module to core
[tests] Factor out unit tests
[btree_builder] Check ordering of pushed key
[all] Fix typos
[array_walker] Simplify error representation for arrays
[tests] Add unit tests for ArrayWalker
[btree] Differentiate non-btree nodes from trashed blocks
[btree] Use enum to represent btree node errors
Split some code out into btree_error
[pdata] Use more descriptive std::io::Error in low-level pack/unpack functions