minor cleanup / standardization

[barrust]

• more standardization across all (most) data structures
  • use of bytes
  • use of MMap class for loading objects
  • additional export type support
  • minor type cleanups
• additional tests

[codecov-commenter]

Codecov Report

Merging #84 (22a8e85) into master (d172fbd) will increase coverage by 0.55%.
The diff coverage is 98.23%.

@@            Coverage Diff             @@
##           master      #84      +/-   ##
==========================================
+ Coverage   98.46%   99.01%   +0.55%     
==========================================
  Files          15       15              
  Lines        1495     1524      +29     
==========================================
+ Hits         1472     1509      +37     
+ Misses         23       15       -8     

Impacted Files	Coverage Δ
probables/utilities.py	96.15% <93.10%> (+0.15%)	⬆️
probables/blooms/basebloom.py	98.78% <100.00%> (+1.98%)	⬆️
probables/blooms/bloom.py	100.00% <100.00%> (ø)
probables/blooms/countingbloom.py	99.17% <100.00%> (ø)
probables/blooms/expandingbloom.py	100.00% <100.00%> (ø)
probables/countminsketch/countminsketch.py	100.00% <100.00%> (ø)
probables/cuckoo/countingcuckoo.py	98.22% <100.00%> (+0.06%)	⬆️
probables/cuckoo/cuckoo.py	98.19% <100.00%> (+1.32%)	⬆️