Hotfix, solving issues with lz4cat.

In detail : Fixed : incompatibility sparse mode vs console, reported by Yongwoon Cho (#105) Fixed : LZ4IO exits too early when frame crc not present, reported by Yongwoon Cho (#106) Fixed : incompatibility sparse mode vs append mode, reported by Takayuki Matsuoka (#110) Performance fix : big compression speed boost for clang (+30%) New : cross-version test, by Takayuki Matsuoka