Performance improvements for VCF I/O.
- Deprecated AsciiLineReader; instead, use LineReaderUtil.fromBufferedStream().  
- Added new BufferedReader-like class, LongLineBufferedReader, with performance improvements for longer-lined files.
- Added an asynchronous line reader, AsynchronousLineReader, which offloads the work of parsing lines into another thread.

git-svn-id: http://svn.code.sf.net/p/picard/code/trunk@1500 8bce386e-0d6e-43e0-b1ca-608082c0432d
Merge remote-tracking branch 'upstream'