* Casting away const isn't undefined behavior, but modifying a constant is

You can cast away `const` as much as you like, as long as you never write to variable.

* rewording for clarification

thus I propose removing R.6 and moving some of its contents into I.2.

* Added two commonly used coding guideline documents

* Update CppCoreGuidelines.md

To adjust example comment and Enforcement per PR #1551 comments

* R.37 : it callees -> its callees
* ES.65 : a different part from the original paper

Clarified the enforcement of C.121 according to #1368

REsolving #1500 with an explanatory note in the introduction.

Adding rule to resolve #1424

To resolve #1356, cleaned up the text for non-rules, eliminating double negatives

Closed #1101

date change

Major changes in R1:
- Added SharedOwner concept.
- Added “Diagnostic sensitivity options” section to define a way to
start with zero-false-positive warnings and increasingly opt into
additional diagnostics.
- Changed function annotation syntax to contract-like pre(cond) and
post(cond) syntax, and added that they are implicitly inherited by
virtual overrides.
- Renamed static to global to reduce confusion with the keyword.
- Refined default lifetimes semantics of Pointer-to-Pointer parameters.

* Address items called out in Issue 1424

* Fix issues caught by CI

* Updates based on PR review

When a reference in the Bibliography is available online, it would seem to be nice to have a link. In this example, the original article was published in C/C++ User's Journal, with the content later ported to the DDJ web site. The DDJ site is no longer reliable, but a good copy exists in archive.org, and I've linked to it here.

Otherwise rather suggests a quadratic growth.

Fixed markdown links in E.15 which direct readers to Github repository, not currently viewing page

The example that is 'intended' to be faster is actually faster on clang 8 /w -O3, and marginally slower than the 'simple' example on GCC 9.1 /w -O3
http://quick-bench.com/DrXvcvhjS1zDmMkgxrzIjbMByYA
http://quick-bench.com/03VXPgDSxiMAmZMItiEA0iwTJgM

typo

It doesn't make sense otherwise

Fixes #1491