'intent' attribute.

  - New cache module, which implements a simple in-memory cache.
  - Async module defines a 'mutex' decorator, which allows instance
    method access to be made mutually-exclusive

a new thread.

2. ImageWrapper marks its expand coverage task thread as a daemon.

because __taskThread attr does not exist.

optionally be told to calculate data ranges on a separate thread.

to collapse many little expansions (that cover individual volumes) into
a few larger ones (that cover many volumes).

equivalent expansions which pertain to adjacent vectors/slices/volumes.

platform module.

be executed.

of coverage, but overlap on some dimensions.

Bugfix in ImageWrapper.calcExpansion - could not handle slice outside of
coverage, but overlapping with some dimensions.

Initial support in Image class for data editing.

regions are specified with nan (which can't be represented as uint32).

function should not be here.

documentation.

tests because i'm impatient.

into a separate method, as it will probably come in handy for write
support.