Lens-style training set support is incomplete

[lplana]

The following features of Lens-style training sets are currently not supported:

• Training sets, known in Lens as example sets, can be applied in six different example orders, described in this section of the Lens manual.
• Training examples can have optional specifications such as name, proc and freq. These specifications are part of the optional example set header, described in this section of the Lens manual.
• Input and target syntax in example files, described in this section of the Lens manual, is not fully-supported. Valid files can fail to compile.
• A training set that does not specify all inputs or all targets, expecting default values to be used, may compile without errors but will produce incorrect results.

Some of these features are required for the example networks provided, such as the simple visual-semantic-phonological network visSemPhon.