Add Makefile for building from CLI

- This is a really basic Makefile to build from command line to make it easy for
  folks who just want to build and run
- Update README
- In ref to #21

Makefile

@@ -0,0 +1,6 @@
+build: clean
+	xcodebuild clean build
+	mkdir bin/
+	mv build/Release/dshb bin/
+clean: 
+	rm -rf bin build

README.md

@@ -33,18 +33,33 @@ An OS X system monitor in Swift, inspired by
 
 Make sure to use the recursive option on clone to auto init all submodules.
 
-```bash
+```sh
 git clone --recursive https://github.com/beltex/dshb
 ```
 
 Incase you have already cloned the repository.
 
-```bash
+```sh
 # Inside the project directory
 git submodule update --init --recursive
 ```
 
 
+### Build
+
+Besides building from inside of Xcode, you can compile dshb from the command
+line like so
+
+```sh
+make
+```
+
+The resulting binary will be found inside the `bin/` directory. If you copy it
+to either `/usr/bin/` (requires `sudo`) or `/usr/local/bin/` (assuming it's in
+your `PATH` - Homebrew would have done this for you), you can then run `dshb`
+from anywhere.
+
+
 ### Stack
 
 - [ncurses](https://www.gnu.org/software/ncurses/ncurses.html)

dshb/main.swift

@@ -195,10 +195,14 @@ draw_all()
 //------------------------------------------------------------------------------
 
 // TODO: Custom serial attr prop creation is new to 10.10
+// dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL,
+//                                         QOS_CLASS_USER_INITIATED, 0)
+
 let source = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0,
                                     dispatch_queue_create("com.beltex.dshb",
                                                          DISPATCH_QUEUE_SERIAL))
 
+// TODO: What about dispatch_after?
 dispatch_source_set_timer(source,
                           dispatch_time(DISPATCH_TIME_NOW, 0),
                           FREQ * NSEC_PER_SEC, 0)