figure out how to run sbt run-main more quietly

[gkthiruvathukal]

When doing actual runs, it would be nice if we can figure out a way to suppress the [info] and [success] lines.

For example:
List Performance reps=10000 size=10000
[info] Loading global plugins from /Users/gkt/dot-sbt/0.13/plugins
[info] Set current project to cs2-listperformance-scala (in build file:/Users/gkt/Work/cs2-listperformance-scala/)
[info] Running Performance 10000 10000
ArrayBuffer fixture creation (size = 10000) = 17 ms
ArrayBuffer reps = 10000 fixture size = 10000 random access = 4 ms
ArrayBuffer reps = 10000 fixture size = 10000 random add/remove = 54 ms
[success] Total time: 0 s, completed Feb 14, 2015 1:27:13 PM

is better as

List Performance reps=10000 size=10000
ArrayBuffer fixture creation (size = 10000) = 17 ms
ArrayBuffer reps = 10000 fixture size = 10000 random access = 4 ms
ArrayBuffer reps = 10000 fixture size = 10000 random add/remove = 54 ms

In my next hack, I may try to output regular CSV and pass it onto something like gnuplot so the performance can be visualized.