introduce maximum recursion time to solve some edge case

[weibinzhu]

under some edge cases, adaptiveOffsetCurve will fail in 'maximum stack' error.

for example: 'M1839.30859375,460.746875 Q1839.30859375,460.796875,1839.30859375,461.064453125 Q1839.30859375,461.33203125,1839.30859375,461.763671875 Q1839.30859375,462.1953125,1838.416015625,467.54296875 Q1837.5234375,472.890625,1830.720703125,486.49609375 Q1823.91796875,500.1015625,1796.701171875,533.046875 Q1769.484375,565.9921875,1748.04296875,586.20703125 Q1726.6015625,606.421875,1666.328125,657.087890625 Q1606.0546875,707.75390625,1541.810546875,757.916015625 Q1477.56640625,808.078125,1405.775390625,868.056640625 Q1333.984375,928.03515625,1285.1640625,971.064453125 Q1236.34375,1014.09375,1203.439453125,1044.802734375 Q1170.53515625,1075.51171875,1154.31640625,1093.408203125 Q1138.09765625,1111.3046875,1136.9921875,1112.2265625 Q1135.88671875,1113.1484375,1136.0078125,1113.02734375 Q1136.12890625,1112.90625,1136.25,1112.90625 Q1136.37109375,1112.90625,1144.734375,1107.583984375 Q1153.09765625,1102.26171875,1177.927734375,1091.029296875 Q1202.7578125,1079.796875,1263.162109375,1055.80078125 Q1323.56640625,1031.8046875,1377.515625,1013.55859375 Q1431.46484375,995.3125,1541.39453125,956.185546875 Q1651.32421875,917.05859375,1751.513671875,882.734375 Q1851.703125,848.41015625,1913.76171875,828.552734375 Q1975.8203125,808.6953125,2062.291015625,784.376953125 Q2148.76171875,760.05859375,2168.400390625,754.890625 Q2188.0390625,749.72265625,2188.3046875,749.72265625 Q2188.5703125,749.72265625,2188.447265625,749.72265625 Q2188.32421875,749.72265625,2188.201171875,749.72265625 Q2188.078125,749.72265625,2187.646484375,749.72265625 Q2187.21484375,749.72265625,2186.783203125,749.72265625 Q2186.3515625,749.72265625,2179.458984375,748.41015625 Q2172.56640625,747.09765625,2164.060546875,743.400390625 Q2155.5546875,739.703125,2149.318359375,736.75 Q2143.08203125,733.796875,2107.666015625,712.548828125 Q2072.25,691.30078125,2031.0859375,657.12890625 Q1989.921875,622.95703125,1929.009765625,575.099609375 Q1868.09765625,527.2421875,1810.4140625,486.525390625 Q1752.73046875,445.80859375,1694.47265625,407.81640625 Q1636.21484375,369.82421875,1610.767578125,353.9921875 Q1585.3203125,338.16015625,1583.203125,336.279296875 Q1581.0859375,334.3984375,1579.98046875,333.6640625 Q1578.875,332.9296875,1578.607421875,332.796875 L1578.28984375,332.6140625'

I introduce a maximum recusion time, 20 times should be enough for a nice offset curve.