Added ability to supply JSON from standard input

README.md

@@ -9,13 +9,26 @@ You will need the following packages: `build-essential` `libsdl2-dev` `libsdl2-i
 Just run `make` and an executable called `trmnl_sdl` should be produced.
 
 # How to use
-1. You will need to write a JSON config file.
-It can either be named `config.json` or you will need to pass it as the first command line parameter to the executable.
+### General use
+1. You will need to write a JSON config file named `config.json`.
 An example structure of the config file can be found in `config_example.json`.
 You can find more info on the available Widgets and their parameters at the end of this file.
 2. Run the executable
 3. Convert the image to a suitable format via an ImageMagick command from below.
 
+### Different ways to supply JSON
+1. Default
+	* Command: `./trmnl_sdl`
+	* JSON Used: `config.json`
+
+2. Specified file
+	* Command: `./trmnl_sdl path/to/json/file.json`
+	* JSON Used: `path/to/json/file.json`
+
+3. Standard input
+	* Command: `./trmnl_sdl -`
+	* JSON Used: Supplied on the standard input for the process.
+
 # ImageMagick commands to prepare image for TRMNL device
 ### Convert image without dithering
 `convert trmnl.png -monochrome -colors 2 -depth 1 -strip png:output.png`