Expanded mapping support

This release:

1. Enables the ability for users to supply their own sex-specific mapping restrictions.
2. Tweaks behavior of aggregating small, numeric counts in the index to support what users might expect. Dates or other non-numeric index values are still recommended.
3. This patch adds a warning for potential impacts of dual-coded mapping with the no-longer-distinct default.

Legacy release

This legacy release of the PheWAS package is to keep backwards compatibility as the approach is retired for the new PheWAS v1.0

Patched pre-v1 update

This release includes some updates to the pre-v1 release code. This is the current best version if one is not using the beta v1.0 branch.

Extended PheWAS methods

This should be the final major release before reworking for pushing to CRAN. It includes a number of alternate statistical approaches with the phewas_ext method.