Added jsondoc compiler switch

Outputs top-level exported information in JSON
Adds fitting quote to idetools doc.
Add stdmsg (an alias to either stdout or stderr).
write exception tracebacks to stdmsg, instead of stdout
Rework CGI error reporting.

- remove 'undocumented' stackTraceNL
- add 'undocumented' errorMessageWriter
- make printing errors for browser optional (for security)
Add two CGI example and basic Python CGI server.
add info about CGI error reporing changes to web/news.txt
Replaces PDoc with var TRstGenerator for documentation.

The PDoc type is a convenience internal alias. Where procs are exported
only documented types should be used to avoid confusing users.
Adds missing ``code-block`` to macros' docstrings.
Adds some docstrings to rstgen.
Updates idetools docs after changes by #743.
Runs user specified outFile if available. Refs #738.
Allows passing absolute paths for output. Refs #738.

Previous to this the project base dir was added always, preventing user
specified absolute paths to work.
Merge pull request #767 from gradha/pr_fixes_run_with_out

Fixes run command with outFile
Merge pull request #753 from gradha/pr_idetools_quote

Adds fitting quote to idetools doc.
Merge pull request #759 from zielmicha/stdmsg

Write tracebacks to stderr instead of stdout.
Update macros.nim
Adds docstring to macros.newIdentDefs.
Merge pull request #768 from fowlmouth/patch-2

Update macros.nim
Merge pull request #764 from gradha/pr_doc_improvements

Documentation improvements