Remove exportPattern() from NAMESPACE

[zkamvar]

At the moment, we are using this as a kludge to export all of the functions that don't start with a dot and it's not a good practice because it makes it difficult to know what functions are for user use and what are for internal use.

Unfortunately, simply removing this breaks a lot of things as the S4 methods suddenly disappear. This is exacerbated by the fact that this package has a hybrid documentation pattern between Rd and roxygen2, which means that we have to find the source of each function and either add and #' export to it or ... something.

[zkamvar]

I'm not going to get this for the next release, but perhaps for 2.1.5