* egil/lcnt:
  Add test suite for lcnt in tools
  Add lcnt:rt_opt/1 bindings to erts_debug
  Add runtime option to enable/disable lcnt stats
  Add auto width on string output
  Add lcnt documentation
  Add lock profiling tool

OTP-8424  Add lock profiling tool.

          The Lock profiling tool, lcnt, can make use of the internal lock
          statistics when the runtime system is built with this feature
          enabled.

          This provides a mechanism to examine potential lock bottlenecks
          within the runtime itself.

          - Add erts_debug:lock_counters({copy_save, bool()}). This option
          enables or disables statistics saving for destroyed processes and
          ets-tables. Enabling this might consume a lot of memory.

          - Add id-numbering for lock classes which is otherwise undefined.

Documentation for the lock profiling tool

          bug was introduced in R13B03. (Thanks to Matthew Sackman.)

In the transition from SGML to XML (several releases ago),
bugs were introduced in the documentation, for instance
"\n" replaced by newlines. Correct those bugs.

Also correct double backslashes. They seem to have been introduced very
early in the development of OTP. According to Lars they "solved" a bug
in the generation of HTML &c. Now that standard tools are used instead
of docbuilder, the bug has become visible.