WarpPerspective: add some mirrors of the input image (Bug #195)

the output image contains the warped input image and a lot of its mirrors when using linear interpolation. this problem does not appears with cubic interpolation.

sample code:

void bugFunction()
{
    CvMat *mat = cvCreateMat(3,3,CV_32FC1);

    //fill the homography matrix
    mat->data.flr0 = 1.04956;
    mat->data.flr1 = -0.75147;
    mat->data.flr2 = 299.216;
    mat->data.flr3 = 0.96346;
    mat->data.flr4 = 0.795854;
    mat->data.flr5 = 454.582;
    mat->data.flr6 = 0.000338058;
    mat->data.flr7 = -1.03816e-005;
    mat->data.flr8 =1;

    IplImage *imIn = cvCreateImage(cvSize(104,32),8,3);
    IplImage *imOut = cvCreateImage(cvSize(1024,768),8,3);

    //draw something onto the input image
    cvZero(imIn);
    cvDrawCircle(imIn,cvPoint(20,15),5,cvScalar(255,0,0),-1);

    //set the output image white
    cvSet(imOut,cvScalar(255,255,255));
    IplImage *imOut2 = cvCloneImage(imOut);

    //that's where the problem is
    cvWarpPerspective(imIn,imOut,mat,CV_INTER_LINEAR);//do some mirroring ?
    cvWarpPerspective(imIn,imOut2,mat,CV_INTER_CUBIC);//or CV_INTER_LINEAR+CV_WARP_FILL_OUTLIERS works also as expected

    //show the expected result
    cvNamedWindow("nobugwin");
    cvShowImage("nobugwin",imOut2);

    //show the non expected result
    cvNamedWindow("bugwin");
    cvShowImage("bugwin",imOut);

    cvWaitKey(100000);

}

running with windows vista 32 bits, visual studio 2008 sp1, IPP enabled.