Don't crash when applications return an error status

This makes watches less frustrating to use

CHANGELOG.md

@@ -0,0 +1,18 @@
+# Change Log
+All notable changes to this project will be documented in this file.
+
+The format is roughly based on [Keep a Changelog](http://keepachangelog.com/)
+and this project adheres to [Semantic Versioning](http://semver.org/).
+
+## [0.3.0] - 2017-04-30
+
+### Added
+
+- This changelog.
+
+### Changed
+
+- Applications returning an error status will now not crash the whole build. The error will be logged into
+  the console and execution will resume as normal. Crashing the whole build was a problem
+  when watching, because often you may save an intermediate file that will not parse and
+  your watch build utility may return an error status.

lib/utils.ex

@@ -296,8 +296,8 @@ defmodule MBU.TaskUtils do
       # Program closed with error status
       {port, {:exit_status, status}} ->
         program = Enum.find(specs, program_checker(port))
-        Logger.error("Program #{program.name} returned status #{status}.")
-        raise "Failed status #{status} from #{program.name}!"
+        Logger.error("[Error] Program #{program.name} returned status #{status}.")
+        handle_closed(specs, port)
 
       # Port crashed
       {:EXIT, port, _} ->
@@ -428,8 +428,8 @@ defmodule MBU.TaskUtils do
         specs
         |> Enum.reject(program_checker(port))
 
-      nil ->
-        # Program was already removed
+      _ ->
+        # Program was already removed or was a watch that shouldn't be killed
         specs
     end
   end

mix.exs

@@ -3,7 +3,7 @@ defmodule MBU.Mixfile do
 
   def project do
     [app: :mbu,
-     version: "0.2.4",
+     version: "0.3.0",
      elixir: "~> 1.4",
      name: "MBU: Mix Build Utilities",
      source_url: "https://github.com/Nicd/mbu",