wip on performance improvements
cache hash codes for Defs and add local indices for getSchedule

Recalculating hash codes can be expensive, in particular for
Reflect nodes that have long lists of dependencies.
reduce dependency blowup: previously a simple effect would depend on all previous effects. now it only depends on the last. this should be cleaned up somewhat and put behind a flag
fixing check files. testSpeculative4 fails due to the previous commit.
using locally built scala 2.10

Scala-Virtualized needs to be installed in `~/.m2`. This is achieved
by running `tools/deploy-local-maven-snapshot` in the scala project
dir. For LMS, `SCALA_VIRTUALIZED_VERSION` needs to be set to
`2.10.0-SNAPSHOT`.
Merge branch 'wip-perf-m7' into wip-scala2.10
updating to 2.10.0-RC1

By default, sbt doesn't query sonatype-releases for Scala
distributions. We need to put the following into
~/.sbt/repositories:

[repositories]
local
typesafe-ivy-releases: http://repo.typesafe.com/typesafe/ivy-releases/, [organization]/[module]/[revision]/[type]s/[artifact](-[classifier]).[ext]
maven-central
sonatype-snapshots: https://oss.sonatype.org/content/repositories/snapshots
sonatype-releases: https://oss.sonatype.org/content/repositories/releases
update to 2.10-RC2
fix test8-speculative4
Merge branch 'develop' into wip-scala2.10

Conflicts:
	src/internal/Effects.scala
update to 2.10.0
add back the checkContext removed from bad merge with develop
Merge pull request #45 from TiarkRompf/wip-scala2.10

Use 2.10.0 in develop