DUB 0.9.20

[Shammah Chancellor]

On 2013-11-30 02:58:50 +0000, Sönke Ludwig said:

> This is planned, but (AFAIK) this is not yet possible in an optimal way
> due to how DMD emits symbols to object files. Currently the only
> reliable way to build incrementally is to compile a single file at a
> time, but this is very inefficient compared to compiling multiple files
> in one go.

Can you even do this when templated symbols are defined in that file?  
This was horribly broken years ago as the templated symbols were 
emitted into the source file that the template was in, rather than the 
including file.