Extract table metadata without Pandas support

[djcomlab]

Right now you can't extract table metadata without using Pandas. In order to at least get something out, we could implement a very lazy loader that only extracts data files lists and factor values to get some summary data from the tables without having to do a full load into memory of the experimental graphs.

[djcomlab]

This is to enable extra metadata to be loaded from within the Galaxy ISA-Tab datatype, as the Galaxy devs don't want to add Pandas to the Galaxy core requirements.

[djcomlab]

Data files and materials now available via 'Lazy' parsers in latest release.