Optimisation: don't write empty chunk
Tests: test empty input
Remove internal ThreadLocal's when done with Executors
OSGi: export new parallel package, don't export impl internal classes
re-introduce convenience API (InputStream, FileChannel)

if you have:
* FileInputStream -> FileInputStream.getChannel()
* RandomAccessFile -> RandomAccessFile.getChannel()
Merge pull request #29 from javabean/dev

Misc changes from our previous email/comments exchanges