Slow functions

[bnicenboim]

eeg_ica_keep()mutate() and select() on channels_tbl (e.g. to change channel namesleft_join(layout_32_1020)

[stonekate]

eeg_downsample()

[stonekate]

plot() - although this may be because of the downsampling
plot_topo() I think too, unless it's changed recently