raster.c: fix possible blank rows appearing in CODE16K, CODE49, PHARMA_TWO,

PDF417 & CODABLOCKF due to height/scale rounding by changing
  out_large_bar_height() to return scaled int values for raster,
  props codemonkey82 (#204)
raster/vector.c: const some vars
vector.c: rect_count, last_start_row UPC/EAN only
library.c: check for stacking symbols >= 200

backend/tests/test_png.c

@@ -197,6 +197,7 @@ static void test_print(int index, int generate, int debug) {
         /* 53*/ { BARCODE_PDF417, -1, -1, -1, -1, -1, -1, -1, -1, 5.0, 0, { 0, 0, "" }, "", "", "Your Data Here!", "", ZINT_WARN_NONCOMPLIANT, "pdf417_height5.png", "" },
         /* 54*/ { BARCODE_USPS_IMAIL, -1, -1, -1, -1, -1, -1, -1, -1, 7.75, 0, { 0, 0, "" }, "", "", "12345678901234567890", "", 0, "imail_height7.75.png", "" },
         /* 55*/ { BARCODE_AZTEC, -1, -1, -1, -1, -1, -1, -1, -1, 0, 0, { 4, 7, "Z1.txt" }, "", "", "3456", "", 0, "aztec_z1_seq4of7.png", "" },
+        /* 56*/ { BARCODE_PDF417, -1, -1, BARCODE_NO_QUIET_ZONES, -1, -1, -1, 5, 8, 16, 1.5, { 0, 0, "" }, "", "", "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBBBBBBBB", "", ZINT_WARN_NONCOMPLIANT, "pdf417_#204.png", "Ticket #204 Blank line in PDF417" },
     };
     int data_size = ARRAY_SIZE(data);
     int i, length, ret;