Create summary method

[dapritchard]

What I am currently thinking is to do something like the show method, i.e. something that prints out the data like a tree, but with effort proportion included.

Perhaps we could have an option for dropping levels that are 0%.

Here's a first pass at what I am imagining.

                                                  Effort proportion
.                                                 -----------------
├── Development projects                                   88% 
│  ├── (+4) A-team                                               3%
│  ├── (+26) asclepias                                          28%
│  ├── (+4) codelist                                             5%
│  ├── (+1) data pipeline orchestration layer                    2%
│  ├── (+8) event-data-model                                    15%
│  ├── (+7) interval-algebra                                     8%
│  ├── (+1) noviverse-site                                       7%
│  ├── (+20) nsBuild                                            17%
│  └── (+1) nsProjects                                           3%
└── Research projects                                      12%
   ├── (+2) P0024 Fracture Prediction                            2%
   ├── (+1) P0025 Osteoporosis Negative Control                  3%
   ├── (+1) P0036                                                0%
   ├── (+3) P0053 Osteoporosis Comparative Effectiveness         3%
   ├── (+5) P0073 Migraine NCO                                   3%
   └── (+1) P0076 market insight PHRs                            1%