sbt/sbt-assembly — pull request #108 by harrah (2014-03-06 12:57:33+00:00)
Title:  Direct implementation of getMappings for speed.

On a build with 70k files in the assembly, this takes the total cached
assembly time from ~50s to 20s. The time due to `getMappings` goes from
~36s to ~4s. From what I could tell, the bulk of the time was due to `IO.relativize`. It is possible there is something lower-level like `IO.relativize` that should be further optimized, but this worked so well I stopped here.