ifstream.tellg() returns -1 on error #516

Currently, the code assumes, that ifstream.tellg() return non-negative values.

source/BAMbinSortByCoordinate.cpp:        uint s1=bamInStream.tellg();
source/Genome.cpp:        size=(uint) stream.tellg();
source/Genome_genomeGenerate.cpp://         nSAbyte=(uint) oldSAin.tellg();

Documentation:

Return Value

The current position in the stream.

If either the stream buffer associated to the stream does not support the operation, or if it fails, the function returns -1.

streampos is an fpos type (it can be converted to/from integral types).

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