v. 1.3-3: PIM and BB tools are feature complete!

Minor updates and code tidyup. Also, added classing and checking to
pim_parse and pim_sum.
fixed the bb_read function check of dropped rows

now get an odd error about max(i)
need to fix
Still had the date wrong!!! oops
Added a check of 0 condition scores

We now give an helpful message that no condition scores are present.
pim_sum median condition now calculated, not mean

this needs to be tested
finished changes from mean to median
Changes to the BB_plot_ca

added a way to automatically add disturbance dates to the plotting
function
update to bb functions

added scientific names to read function and options for plotting
disturbances to bb plot ca function
Resolving conflicts
G's additions, merge