Add --install-actions and --install-prefix

These flags are used when --install is given.

--install-actions is boolean and determines whether or not to run
the installation actions (notify launchd, etc).
--install-prefix is a string letting you tell pleaserun
where to write files to. This is intended to help packagers.

This should satisfy #43

lib/pleaserun/cli.rb

@@ -21,6 +21,8 @@ class PleaseRun::CLI < Clamp::Command # rubocop:disable ClassLength
   option "--json", :flag, "Output a result in JSON. Intended to be consumed by other programs. This will emit the file contents and install actions as a JSON object."
 
   option "--install", :flag, "Install the program on this system. This will write files to the correct location and execute any actions to make the program available to the system."
+  option "--[no-]install-actions", :flag, "Run installation actions after writing files", :default => true
+  option "--install-prefix", "DIRECTORY", "The path to prefix file paths with. This flag is generally intended for packagers, not for users installing directly on systems.", :default => "/"
 
   option "--verbose", :flag, "More verbose logging"
   option "--debug", :flag, "Debug-level logging"
@@ -167,8 +169,8 @@ def run_json(runner)
 
   def run_human(runner)
     if install?
-      PleaseRun::Installer.install_files(runner, "/", overwrite?)
-      PleaseRun::Installer.install_actions(runner)
+      PleaseRun::Installer.install_files(runner, install_prefix, overwrite?)
+      PleaseRun::Installer.install_actions(runner) if install_actions?
     else
       tmp = Stud::Temporary.directory
       actions_script = File.join(tmp, "install_actions.sh")

spec/pleaserun/cli_spec.rb

@@ -0,0 +1,23 @@
+require "pleaserun/cli"
+
+describe PleaseRun::CLI do
+  subject { PleaseRun::CLI.new("pleaserun") }
+
+  context "when setting --install-prefix" do
+    let(:output) { Stud::Temporary.directory }
+    let(:name) { rand(10).times.collect { (rand(26) + 97).chr }.join }
+    let(:args) { [ "--install", "--install-prefix", output, "--no-install-actions", "-p", "sysv", "-v", "lsb-3.1", "--name", name, "/some/example" ] }
+
+    before do
+      subject.run(args)
+    end
+    after do
+      FileUtils.rm_r(output) if File.directory?(output)
+    end
+    it "should write files there" do
+      [ "/etc", "/etc/init.d", "/etc/init.d/#{name}" ].each do |path|
+        expect(File).to be_exists(File.join(output, path))
+      end
+    end
+  end
+end