Problems with the JANA2 tutorial

[nathanwbrei]

This is for accumulating and tracking problems that Takuya is encountering while working through the tutorial.

[nathanwbrei]

• Are we building individual plugins in the 'src' directory or not? Confusion over how much project structure we are using. I'm kind of tempted to use more project structure, and put each new component (and the datamodel) in their own plugin/library. Perhaps if we are clever we could make it so that users can follow the tutorial while adding code within the EICrecon or halld_recon project trees. Remember that virtually all of our users are coming from ePIC or gluex.

• cmake3 doesn't exist in eic-shell, and should really just be cmake

• Tutorial tells user to run processor with no source, which crashes (See issue Attempting to run with no event sources throws an ArithmeticException #437). There should be more exposition telling the user that we are just verifying that JANA2 can find the plugin they just built, but that the plugin can't run because it doesn't have any source of data yet.

• JOBJECT_PUBLIC is not in the tutorial but IS in the generated code, with no explanation

[nathanwbrei]

jana-generate.py JFactory <factory_typename> <data_typename> was changed to jana-generate.py JFactory <data_typename> <tag>. It also appears to re-generate the JObject header, whereas the tutorial does this as a separate step. If the user modified the JObject, this would overwrite it.

[11kumaoka]

The command, "jana-generate.py JFactory SimpleClusterFactory Cluster", makes three files "SimpleClusterFactory.h, JFactory_SimpleClusterFactory_Cluster.cc, JFactory_SimpleClusterFactory_Cluster.h".
However, the tutorial page expects "SimpleClusterFactory.h" is existing "Cluster.h" and "JFactory_SimpleClusterFactory_Cluster" is "SimpleClusterFactory".
And in the following steps, we need to replace "SimpleClusterFactory" to "JFactory_SimpleClusterFactory_Cluster".