Do not increase contract versions before a stable application records them #94

Problem

#88 increased to version 2 eleven contracts whose result changed since 1.3.0 (#87). The contracts are a new feature of Sigima 1.3.0 (published four days earlier), only used so far by DataLab-Web 0.x, which is not in production; DataLab 1.4, the first stable application recording them, is not released, and the capsule format is experimental (0.1). No recorded activity has to be refused: version 2 only refuses theoretical recordings, while it makes the reference files of DataLab (recorded with version 1) non-replayable and requires DataLab-Web to follow. This is also inconsistent with an earlier decision not to increase contract versions before their adoption.

Proposal

• Revert Increase the operation contracts whose result changed since 1.3.0 #88: the eleven contracts (and their qualifications) go back to version 1; the changes of Sigima 1.4 are part of version 1.
• Keep the decision rule of the guidelines, and state that version 1 is settled by the first stable release of an application recording the contracts (DataLab 1.4): until then, versions are not increased.
• Keep the image ROI pixel convention recorded in the execution context (Record the selection of image pixels by ROIs in the execution context of calls #89/Record the image ROI pixel convention in the execution context #92), which versions this convention for the future without increasing every image contract.