Make classes upper case again

[Funth0mas]

When merging the 'typing' branch I realized that some classes was unwillingly refactored to snake case.

[ebroecker]

... what do you think, should classes be snake_case or camelCase?
I don't know.
We only discussed lossely in #236 to switch to snake_case.

In all cases, you are right, its not consistent as is now.

[altendky]

UpperCamel is what pep8 suggests for normal situations.

https://www.python.org/dev/peps/pep-0008/#class-names

[codecov-io]

Codecov Report

Merging #298 into development will not change coverage.
The diff coverage is 78.26%.

@@             Coverage Diff              @@
##           development     #298   +/-   ##
============================================
  Coverage        37.81%   37.81%           
============================================
  Files               34       34           
  Lines             6820     6820           
  Branches          1675     1675           
============================================
  Hits              2579     2579           
  Misses            4023     4023           
  Partials           218      218

Impacted Files	Coverage Δ
src/canmatrix/xls.py	10.58% <0%> (ø)	⬆️
src/canmatrix/kcd.py	5.05% <0%> (ø)	⬆️
src/canmatrix/xlsx.py	1.05% <0%> (ø)	⬆️
src/canmatrix/dbf.py	4.22% <0%> (ø)	⬆️
src/canmatrix/canmatrix.py	71.87% <100%> (ø)	⬆️
src/canmatrix/dbc.py	50.07% <100%> (ø)	⬆️
src/canmatrix/tests/test_canmatrix.py	100% <100%> (ø)	⬆️

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[ebroecker]

Thanks again