drop httpclient dependency, which wasn't actually being used by Ivy
account for localOnly when cache subclass overrides isChanging
Fix for cache issues when developing sbt itself.

Ivy still seems to remember the resolver that found the metadata
and records that as the resolver to use for the artifact.  Previous
fixes have attempted to ignore or blank this resolver.  The issue
this fix addresses comes from inter-project not being ignored/blanked.
inter-project can't provide artifacts because it is only for projects
in the current build under development and not for modules in a repository.
The symptom is that compiling a build definition fails because the
sbt jars aren't on the classpath, but it is ultimately due to the
inter-project resolver incorrectly being used to resolve artifacts.
0.13.0-M2
update change summary for 0.13.0-M2
snapshot version
Include files with zip extension in unmanaged jars.  Fixes #750.
Docs: fix typos on Input-Tasks page
use Option constructor instead of Some for potentially null file lock
Derived settings, which allows injecting settings wherever their dependencies are defined.

This is an advanced feature initially intended for internal sbt use.
display derived settings information in 'inspect'
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