ensure a derived setting is only injected into a scope once
require dynamic initialization to be explicitly enabled for derived settings
more specific error when dependencies of a derived setting are undefined
support filtering the Scopes that a derived setting is applied in
Default settings, which give internal sbt settings something like Plugin.globalSettings.
only derive settings when all dependencies are defined
tests for derived settings
Show defining locations when there are cycles between derived settings
In 'set' command, handle keys in new scopes in the affected settings part
Derived settings: handle scopeLocal in derive and allow triggering dependencies to be filtered
Derive testGrouping,compilers,scalaBinaryVersion.  Don't go through compileInputs for doc.  Fixes #539, #708, #391.
Docs: cleanup related to generating sources+resources
Docs: note that source generators can generate Scala and Java sources together.
Put summary not available message at the debug level.  Review by @cheeseng.
Update reflection signature for scripted plugin, add test for the plugin.
Make imports from MurmurHash explicit for clarity.
Merge ExtendedReporter into Reporter.
local SyncVar implementation to deal with std lib deprecations
Use the recommended sbt.log.format property instead of noformat in the docs
sbt.log.format should not be set by sbt, since that will not respect noformat