Add dataTable chart type to wdcplot, add simple R variable substitution to wdcplot calls
Revert to original parameter names
Data weighting and stacked bar charts enhancements
Data weighting and stacked bar charts enhancements
dependencies_bundle.min.js cleanup
Margin change
Merge remote-tracking branch 'upstream/develop' into develop
Merge branch 'develop' of https://github.com/bartbutler/rcloud into bartbutler-develop
whitespace & semicolons
apparent mistaken reference to group definition defreduce
default defreduce when no groups specified
simpler definition of do_weights
missing semicolons and variable declarations
trailing whitespace
three-pass substitution of wdcplot expressions on R side

1. bquote to evaluate arbitrary expressions in R
2. substitute column placeholders and special variables
3. substitute in parent environment

With this commit, column placeholders and special variables are proper
classes which are interpreted in wdcplot.js - no more hacky special string names,
and string literals are (or should be) safe again!

Extensive changes to expression processing on JS side - needs further testing,
but far more robust in principle.

closes #156
missing variable declaration
missing variable declarations
use _.clone instead of jQuery.extend({},
line breaks
variable declarations, spacing, semicolons