loongson/pypi: links for cebstemmer

loongson/mirror cebstemmer-1.6.zip
loongson/mirror cebstemmer-1.5.zip
loongson/mirror cebstemmer-1.4.zip
loongson/mirror cebstemmer-1.3.zip
loongson/mirror cebstemmer-1.2.zip
loongson/mirror cebstemmer-1.1.zip
loongson/mirror cebstemmer-1.0.zip