Fixes #192 via nested and remove using

[ckormanyos]

No description provided.

[ckormanyos]

Ooops. I had inadvertently deleted the branch of a running CI/PR. This should correct that.

[ckormanyos]

Hi @johnmcfarlane this wraps up the first phase of clang-tidy fixes. I really wanted all (that I could detect) of modernize-* --- which is now in theis PR.

I am actually going to (from this point) hold off on further CT activities until you make a drive forward on that. There is no hurry for this and this serves to simply inform that I'm at a stable equilibrium at the moment and wait until you move forward. If/when that occurs, I'll sync up with your removal of CT exceptions.

This PR, I believe, gets wide-integer and all its test and example code CT-tidy with the exceptions:

  *,
  -altera-id-dependent-backward-branch,
  -altera-struct-pack-align,
  -altera-unroll-loops,
  -fuchsia-*,
  -llvmlibc-*,
  -llvm-header-guard,
  -readability-avoid-const-params-in-decls

[ckormanyos]

After this, I'll look into #194 and #183 and #169, and after all that finally re-visit #91

Cc: @johnmcfarlane