Add and fix cpplint whitespace/comments

[cbachhuber]

Finalizing the work started in #400 (and part of #378): this PR enables the cpplint check whitespace/comments and fixes corresponding issues.

Also, it aligns the clang-format style to 2 spaces between code and trailing comments.

[codecov]

Codecov Report

Merging #434 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master   #434   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          12     12           
  Lines        3582   3582           
=====================================
  Hits         3582   3582

Impacted Files	Coverage Δ
include/CLI/Config.hpp	100% <ø> (ø)	⬆️
include/CLI/Split.hpp	100% <ø> (ø)	⬆️
include/CLI/Error.hpp	100% <ø> (ø)	⬆️
include/CLI/Timer.hpp	100% <ø> (ø)	⬆️
include/CLI/ConfigFwd.hpp	100% <ø> (ø)	⬆️
include/CLI/Option.hpp	100% <100%> (ø)	⬆️
include/CLI/Formatter.hpp	100% <100%> (ø)	⬆️
include/CLI/App.hpp	100% <100%> (ø)	⬆️
include/CLI/StringTools.hpp	100% <100%> (ø)	⬆️
include/CLI/TypeTools.hpp	100% <100%> (ø)	⬆️
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 80d8e94...d8c146a. Read the comment docs.

[cbachhuber]

clang-format now requires test code also in proper formatting. Should we add folder tests to cpplint checks? I just checked, with the current cpplint configuration, there are 23 legal/copyright issues in tests, and 11 other issues.

[phlptp]

In general I think it is a good idea to treat the test code the same as the library code, so I would be in favor of running any checks on the test code. With the knowledge that I am pretty sure there are a few cases where we are purposely doing something Abnormal for the purpose of testing some aspect of the library, so there will likely be a few places where we have bypass the checks.

[phlptp]

I would enable the test checks in a separate PR though.

[henryiii]

I second that. Tests and (usually) examples should be included in checks. Second PR is best.

[cbachhuber]

Got it, I'll create a separate PR for including tests in cpplint and fixing the corresponding issues 👍