make test of mirroring models easier to modify
model runs: add interface globals to mirrorable observer
model runs: expose small api for load/save
model runs loader: avoid ugly workspace dependency
model runs: package reorg
mirroring: build diffs with Buffer for better performance in Scala 2.10
Merge remote-tracking branch 'origin/modelruns-2.10' into modelruns

Conflicts:
	headless/src/main/org/nlogo/mirror/Mirrorables.scala
Merge remote-tracking branch 'origin/master' into tortoise