Refactor 'Read' Class

[emcd]

While working on improvements to the Python wrapper, it occurred to me that we might want an 'IRead' class with inheritors, such as 'FASTARead' and 'FASTQRead'. This mimics the parser hierarchy and I think it may be appropriate for several reasons:
() The current interface is a fat interface - quality scores are unused in FASTA processing.
() We would be carrying some information on original format in the type of the read. (Currently, this information is not really tracked anywhere during processing.)

An even more radical idea, which I am not necessarily advocating at this point, would be to supply 'read' and 'write' methods for the read classes. This would relegate the reader/parser classes to more of a facilitator/manager role around the shared resources (such as input streams), and would do likewise for any writer/formatter classes. Just something to think about.... have not seriously considered either a particular design or any performance trade-offs associated with such a design yet.

[ctb]

I like your more radical idea. +1

Can't imagine there would be substantive performance trade-offs...

[ctb]

See #92 / threaded output writing.