README: reformat as Markdown (bleh)

README.md

@@ -1,12 +1,12 @@
-h1. Candid Words
+# Candid Words
 
 This is a basic algorithm for generating a list of Wordle candidates based on yellow and green tiles.
 
-h2. Building
+## Building
 
-You will need a C++11 compiler, for instance @g++ -std=c++11@. If you want to use a specific word list, save it as a plaintext file at 'words.txt' and run @convert.py@ before compiling the program.
+You will need a C++11 compiler, for instance `g++ -std=c++11`. If you want to use a specific word list, save it as a plaintext file at 'words.txt' and run `convert.py` before compiling the program.
 
-h3. Copyright
+## Copyright
 
 The code is made available under BSD-3-Clause.