More updates towards supporting function documentation:

More updates towards supporting function documentation:
* Convert \f[BI].*\fP strings containing white space to quoted .B lines.
* Anchor conversion of \f[BI] lines to .[BR] at end of line.
* Convert \f[BI] lines preceded by text to a .R[BI] line.
* Convert -- on .[BI]R? lines to \-\-.
* Support  global="0" and env="0" options <scons_function> arguments for
  when the function has no global form or construction environment form.

git-svn-id: http://scons.tigris.org/svn/scons/trunk@4689 fdb21ef1-2011-0410-befe-b5e4ea1792b1