Add a parameter for the size of th wells in *_map and *_grid functions

[matushiq]

It would be nice and helpful to be able to adjust the size of the wells in the final figure.

[Swarchal]

Sounds a good idea, should be fairly easy to add this as an optional parameter

[Swarchal]

I've exposed the size and shape arguments in geom_point, so you should be able to use these in most of the _map and _grid functions (apart from the median smoothed ones, but I'll sort fix those shortly).

You should be able to use these if you install from github.

example:

library(platetools)

df = data.frame(vals=rnorm(96), wells=num_to_well(1:96))
raw_map(data=df$vals, well=df$wells, size=15, shape=22)

df = data.frame(vals=rnorm(96), wells=num_to_well(1:96))
raw_map(data=df$vals, well=df$wells, size=8, shape=21)