Expand the README

Copies useful bits of documentation over from Images

README.md

@@ -5,6 +5,61 @@
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-Seperated ImageMagick from Images.jl to make ImageIO more lightweight.
+This package was split off from [Images.jl](https://github.com/timholy/Images.jl) to make image I/O more modular.
 
-Credits go to: [Images.jl](https://github.com/timholy/Images.jl)
+# Installation
+
+Add the package with
+
+```jl
+Pkg.add("ImageMagick")
+```
+
+# Usage
+
+ImageMagick will be used as needed if you've said
+
+```
+using FileIO
+```
+
+in your session or module. You should **not** generally say `using
+ImageMagick`.  See [FileIO](https://github.com/JuliaIO/FileIO.jl) for
+further details.
+
+It's worth pointing out that packages such as Images load FileIO.
+
+# Troubleshooting
+
+## OSX
+
+ImageMagick seems to experience trouble frequently on OSX. If
+[QuartzImageIO](https://github.com/JuliaIO/QuartzImageIO.jl) works for
+you, it may be an easier solution.
+
+If you do want to fix your ImageMagick installation, before asking for
+help please try the following sequence:
+
+```{.julia execute="false"}
+using Homebrew
+Homebrew.rm("imagemagick")
+Homebrew.update()
+Homebrew.add("imagemagick")
+Pkg.build("Images")
+```
+
+You may also find [debugging Homebrew](https://github.com/JuliaLang/Homebrew.jl/wiki/Debugging-Homebrew.jl) useful.
+
+## Manual installation on Windows
+
+If automatic installation fails, get the current version from
+http://www.imagemagick.org/script/binary-releases.php#windows
+(e.g. ImageMagick-6.8.8-7-Q16-x86-dll.exe) and make sure that the "Install
+development headers and libraries for C and C++" checkbox is selected.  You may
+choose to let the installer add the installation directory to the system path or
+provide it separately.  In the later case you may add it to your `.juliarc.jl`
+file as (for example) `push!(Base.DL_LOAD_PATH,
+"C:/programs/ImageMagick-6.8.8"`). Alternatively, you can set your `MAGICK_HOME` environment variable.
+
+**When manual intervention is necessary, you need to restart Julia for the
+necessary changes to take effect.**