reader: get_block_zlib_decompress(): handle Z_BUF_ERROR from inflate()
reader: get_block_zlib_decompress(): handle Z_BUF_ERROR from inflate()

for highly compressed data, the output buffer we pass to zlib's
inflate() may not be large enough to contain the decompressed data
block. call inflate() in a loop, enlarging the output buffer as
necessary.

this addresses the MTBL_COMPRESSION_ZLIB case for Issue #1.

farsightsec/mtbl,farsightsec/mtbl,rep/mtbl,snarkmaster/mtbl,rep/mtbl,rep/mtbl,snarkmaster/mtbl,snarkmaster/mtbl