Cluster management code
Add cluster lapply
Add progress bar manager
Expand progress bar examples
Update docs
Initial implementation of do
Re-document
Improve examples
Support multiple grouping vars
Add min_time to progress bar
Tweak progress bar interface
Add automatic progress bar to do
Better printing for list columns
Pass n argument on from print to trunc_mat
Tweak examples and fix buglet
Start writing some tests
Add reasonable do() behavour for ungrouped data frames
Fix typo in tbl_dt
In tbl_dt, set explicit class
Move do methods into one file