support on windows with pthread

1. Some lines has been added to support build on windows.
2. There was couple of old bugs in hash table calculation in the file I2Ohash/util.c. This bugs only reveals if you make build on 32 bit system and will try calculation for matrices which indices bigger then 2^16. Multiplication of such indices will not fit into 32 bit integer and may became negative. So the solution is to convert 32 bit integers into 64 bit during calculation.