Changed makeSnapshot and render methods

git-svn-id: svn+ssh://svn.abisource.com/svnroot/abiword/branches/gsoc2013lasem@33261 bcba8976-2d24-0410-9c9c-aab3bd5fdfd6
buildSnapshot directly writes to UT_ByteBuf

git-svn-id: svn+ssh://svn.abisource.com/svnroot/abiword/branches/gsoc2013lasem@33262 bcba8976-2d24-0410-9c9c-aab3bd5fdfd6