Remove significant figure transformations included in mc3.R and sc1.R

[madison-feshuk]

In mc3.R and sc1.R, there's a line that forces conc to truncate to 1 significant figure. This results in conc being rounded up/down depending on value. Let's remove this line so real conc values can be stored

CompTox-ToxCast-tcpl/R/mc3.R

Line 58 in c61f7d1

## Force all concentrations to 1 significant figure

CompTox-ToxCast-tcpl/R/sc1.R

Line 62 in c61f7d1

## Force all concentrations to 1 significant figure

tcplLoadData of mc3 loads joins with mc0 so real values were fit. @cthunes found this bug within plotting since mc4_agg pulls from mc3 table directly