adding absolute value plots, checking input variable list
very basic programmatic testing of plots
plotting data in order
using a helper function to assist testing of plotting
starting a balanceplot function, which plot.xbal will call
Merge branch 'variable-groups' into balance-plots
using lattice to make grouped balance plots
removing commented out lines, dot plot line less prominent
ordering data by imbalance
Revert "ordering data by imbalance"

This reverts commit 2d22eebf7f1487430876017a97ad41b9eb90ad62.
Revert "removing commented out lines, dot plot line less prominent"

This reverts commit 2a8e401d418add7f8f12f61d179d2b3b4750e2f7.
Revert "using lattice to make grouped balance plots"

This reverts commit f10b296787ea30d3c996a85d82f0285c767c79da.
using basic R graphics for generic plots, grouping
legend prints at the top of the diagram
rdoc for balanceplot
adding examples to balanceplot docs, small changes to same
setting par() values
fixing histeresis of plotting params
plot.xbal uses balanceplot function
moving the absolute arg to the plot.xbal function