Replace SNFMilterContext::SkipReturn with global variable SkipReturn
(in file SNFMilter.cpp). Implemented assignContextToCtx to assign a
SNFMilterContext object.
git-svn-id: https://svn.microneil.com/svn/SNFMilter/trunk@7 2c985dca-31e6-41a4-b4a2-d8f5b7f8e074