Added getDataSubVolume methods.

(1) Added getDataSubVolume and getDataSubVolumeRM methods with
corresponding test cases in IceImarisConnectorTestUnit. (2) Streamlined
findImaris a bit. (3) Increased version number to 0.3.0.
Increased version number to 0.3.0.

This was erroneously stated in the previous commit detailed message.
Added option to specify to which container to add new spots in createAndSetSpots().

Moreover, added missing function declaration in IceImarisConnector.m.
Corrected type.

Corrected typo in an error message.
Added the isSupportedPlatform() static method.

Moreover, removed the 'this' argument to the static method version().
(1) Removed declaration for no-longer existant setSpots method. (2) Added isSupportedPlatform.m. (3) Updated VERSION file.

(1) This was temporarily added long time ago. (2) The function was
defined within IceImarisConnector and the createAPI function would not
extract its documentation.
Merged devel branch into master.

Ready for 0.3.0 release.