multicolumn save/load

Now persisting the current number of grid columns in saved freeboards,
and resetting the columns to the saved state on load.
grunt minified
fix for multicolumn save/load

We now save the columns field as the maximum number of columns for which
a grid layout has been specified.

If, when loading a saved freeboard, the specified number of columns in the
columns field is greater than the available width, we default to the maximum
number of columns that fit on the current screen.
grunt minified
fix copy-paste error and minify
save manual columns count

If the user manually sets the number of columns via the add/subtract
column buttons, ignore the maximum defined layout when saving the
freeboard and instead use the user-defined value.
grunt minify
Bug fixes, and file renaming
Merge branch 'refs/heads/add_subtract_columns' into gh-pages