Enable doc-tests (#56)

* Project is now a library with main-like function to enable doc testing

* fixed not working doc-tests

* fmt

Author: tudny

Cargo.toml

@@ -13,6 +13,11 @@ authors = ["Mieszko Grodzicki", "Aleksander Tudruj"]
 name = "jp2gmd"
 path = "src/main.rs"
 
+[lib]
+name = "jp2gmd_lib"
+path = "src/lib.rs"
+doctest = true
+
 [features]
 fft = []
 clock = []