avoid string decoding recoding
Merge pull request #19 from Parquet/improve_thrift_perf

avoid string decoding recoding
add better Bytes plain decoder
fix perf test
fix offset
test other bitpacking approach
fix perf problem with new String(bytes, offset, length, encoding)
remove one array copy
better bit packing impl
Merge branch 'perf_improvement' into bit_packing_improv

Conflicts:
	parquet-column/src/main/java/parquet/example/DummyRecordConverter.java
	parquet-column/src/test/java/parquet/io/PerfTest.java