Imagedata

* Added get_transporter_list() to imagedata.transports.
* Added get_archiver_list() to imagedata.archives.

Added
* Added documentation on viewing.

Changed
* Series.get_roi_mask(): Return 2D mask when original images is 2D.
* Viewer: Display image text even when some attributes are missing.
* Viewer: Better presentation of window center/width when they are floats.
* Viewer: Reimplemented PageDown/PageUp to scroll one page at a time.
* Viewer: Adjusting window center/width is modified to use
series min/max, not existing window.
Will improve user feedback when window is unreasonable.

Added
* Viewer: Ctrl+Home/End will scroll to first/last series.
* Viewer: Ctrl+Array Left/Right will scroll one series.
* Viewer: Ctrl+Array Up/Down will scroll one row of series.
* Viewer: Toggle the hide text will affect all series.

Changed
* Series.fuse_mask(): Corrected scaling of mask range to colors.

Added
* Documentation on using color Series objects.

Changed
* RGB-image representation.
Use NumPy structured dtype to represent color data.
Simplify index calculations when color is not a dimension.
* fuse_mask(): Accept variable mask, rendered in a specified colormap.
* fuse_mask(): Save color map for later viewing.
* Viewer: Display color map when this exists.