invoke Shiny knit_print in Shiny R Markdown documents
allocate space for controls in document
scope change to Shiny versions supporting ::shinyApp
Merge pull request #135 from rstudio/feature/shiny-docs

Support for interactive ggvis objects in Shiny documents
fix ggvis #129

Don't know what this "+ 1" was supposed to do. When I made it not crash by converting keys to numeric, it selected the wrong objects in the linked plot. Without + 1 it works as expected.
Merge pull request #138 from ThomasSiegmund/master

fix ggvis #129
Add magrittr dependency
First changes for new syntax
Don't explicitly store data_id or props_id
Rename 'chidren' to 'layers'
Modifications to as.vega to make basic plots work
Get transform_sort working
Fix props ID calculation
layer_point: simplify data ID code
Add visualize alias
Add register_data function
Migrate all marks to new format
Reorganize code
Add explain() function
Rename visualise to ggvis