Add support for Tiff and JPEG2000

This PR adds support for exporting slices in tiff and Jpeg2000.
Close #104 (closed) and #105 (closed).

To do:

• io.writer.TIFFWriter
• Test io.writer.TIFFWriter
• io.writer.JP2Writer
• Test io.writer.JP2Writer
• Integrate TIFF in pipeline
• Integrate JPEG2000 in pipeline

Questions

• TIFF: Not sure if we should be using silx.third_party.TiffIO or Gohlke's tifffile ?
• JP2K: Which interface do we provide in configuration ? Fixed PSNR of fixed compression rate ? I would go for fixed PSNR.

Left for later:

• Normalization: for now data is "normalized" image by image. For jpeg2000, as the data has to be in uint16, the data range is taken for each image (instead of the whole volume).
• Advanced parameters: data type (tiff), PSNR (jpeg)