ggplot2 is working on a new theming system

[briandk]

It's not in production yet, but once it goes into production it will likely break our current theme structure. I'll have to be clever if we're going to attempt to preserve backward-compatibility down the line:

https://github.com/wch/ggplot2/wiki/New-theme-system

https://groups.google.com/forum/m/?fromgroups#!topic/ggplot2-dev/2Hdy3iO46nM

[briandk]

We ended up deciding not to preserve backward-compatibility.

See also:

• Issue #151
• Commit 42c2aafbc497eeb868d89a09ed8b59cb3a539244