Create documentation paradigm for modules

[eliotmcintire]

This is the general issue for #21 #22 #23 #24 #25

[eliotmcintire]

I started with using roxygenize2 ideas, but it may need more thought. Maybe it is fine. See commit a76db0e

[achubaty]

Module metadata at top of the module's .R file should include (at minimum) the following metadata:

1. brief description of the module
2. author and contact info
3. identify the type of license under which the module can be used (see below)
4. identify all additional files that document the module (see below)

---

Module distribution

Hosted in a separate GitHub repo (PredictiveEcology/SpaDES-modules), with each module contained in a separate subdirectory. The entire contents of a module subdir can be distributed as .zip file. Each module sub directory is named after the module and does not contain version info (this will be provided as part of the metadata, etc. per below). Distributed (and archived) .zip files could be named with the version number if desired.

Module data will NOT be included/hosted in our repo. They must be accessible elsewhere, and code/instructions for this step should be included in the module documentation.

Modules can be contributed to our repo via pull requests, which also provides easier quality assurance on our part with respect to contributed modules' structure and documentation.

Module directory structure:

    /
    |_ moduleName/
        |_ moduleName.R            # the actual module code file, incl. module metadata
        |_ moduleName.Rmd          # longform documentation and usage info, etc.
        |_ citation.bib            # properly formatted bibtex citation for the module
        |_ LICENSE                 # license file describing the allowed usage etc. of the module
        |_ README                  # incl. module metadata in addition to version change info, etc.
    |_ moduleName.zip
    |_ moduleName0.1.0.zip

[eliotmcintire]

All done except .zip files because they are not relevant until the module has real files worth zipping. 3e6608d 697322f 7c74e10.

[eliotmcintire]

Still need to change the simInit function, so that path argument is the base folder for modules, and modules are subfolders within that.

[achubaty]

other than updating the sample module docs as noted in 3b1b0e7, I think this can be closed.