A set of changes reflecting some of the final integration of the climate data with the pollen data.  Dome minor changes in the Rmd file, inclding the addition of `rm` statements.  Some plot changes, as well as some analysis allowing us to calculate valid p values.

Changes to `analogue_function.R` are mostly to avoid bugs, also adds a plotting component to find_analogues that seems to crap out sometimes.

In `calculate_turnover.R` I dropped the period in `set.frame`, it's not `set_frame` to match the standard in the ply functions.  Changes also include dropping some pollen taxa in the analysis.

Added package loading to `load_datasets.R`.
Moved library statements to `load_datasets.R`, changed file name in load_datasets.R to link to RData instead of Rdata.