Fixes #373: Go 1.7 context package import issues

dependency/resolver.go

diff --git a/dependency/resolver.go b/dependency/resolver.go
index dc88f62..f53ae2f 100644
--- a/dependency/resolver.go
+++ b/dependency/resolver.go
@@ -872,6 +872,12 @@
 		// https://blog.golang.org/the-app-engine-sdk-and-workspaces-gopath
 		info.Loc = LocAppengine
 		r.findCache[name] = info
+	} else if name == "context" {
+		// context is a package being added to the Go 1.7 standard library. Some
+		// packages, such as golang.org/x/net are importing it with build flags
+		// in files for go1.7. Need to detect this and handle it.
+		info.Loc = LocGoroot
+		r.findCache[name] = info
 	}
 
 	return info

tree/tree.go

diff --git a/tree/tree.go b/tree/tree.go
index 8f0a0b5..86977e5 100644
--- a/tree/tree.go
+++ b/tree/tree.go
@@ -167,6 +167,11 @@
 		// where Google products are playing with each other.
 		// https://blog.golang.org/the-app-engine-sdk-and-workspaces-gopath
 		info.Loc = dependency.LocAppengine
+	} else if name == "context" {
+		// context is a package being added to the Go 1.7 standard library. Some
+		// packages, such as golang.org/x/net are importing it with build flags
+		// in files for go1.7. Need to detect this and handle it.
+		info.Loc = dependency.LocGoroot
 	}
 
 	return info