[WIP] Rewrite MATLAB import functions with readstruct()

[Jerry1144]

One path to #343, rewriting trackmateSpots.m with readstruct() function. Shifting to MATLAB's own capabilities helps alleviate Java heap size problems.

Specific to this path:

1. readstruct reads everything, so calling out to trackmateFeatureDeclarations for parsing FeatureDeclarations feels wrong.
2. struct field names may have been changed (according to MATLAB identifiers rule). There's additional logic to guess the original XML Attribute name. May consider moving to a separate function for code reuse.

Future plan is to have the separate trackmateFeatureDeclarations.m accept a structure as a secret input, to avoid loading the XML again when the calling function has already done it.

• trackmateSpots.m
• trackmateFeatureDeclarations.m
• trackmateEdges.m
• trackmateGraph.m
• trackmateImageCalibration.m

[tinevez]

Cool! Ping me when you are ready.

[Jerry1144]

Superseded by #350. Closing.