Merged revisions 2117-2120 via svnmerge from

Merged revisions 2117-2120 via svnmerge from
http://scons.tigris.org/svn/scons/branches/core

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  r2119 | garyo | 2007-07-11 08:53:36 -0500 (Wed, 11 Jul 2007) | 1 line

  Fixed minor cut/paste doc error
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  r2120 | stevenknight | 2007-07-11 12:42:50 -0500 (Wed, 11 Jul 2007) | 4 lines

  Simplify the {Add,Get,Set}Option() implementations, and initialize the
  OptionsParser variable with a do-nothing class, in case it's used
  by test scripts without normal SCons.Script.Main initialization.
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git-svn-id: http://scons.tigris.org/svn/scons/trunk@2121 fdb21ef1-2011-0410-befe-b5e4ea1792b1