Add Maxima (#1372)

Author: abt8601

m/Maxima.max

@@ -0,0 +1 @@
+print("Hello World")$

readme.md

@@ -8,7 +8,7 @@ Thanks to everyone who continues to contribute; new languages are created every
 Make sure to see [contributing.md](/contributing.md) for instructions on contributing to the project!
 
 <!--Languages start-->
-## Languages (933 total)
+## Languages (934 total)
 
 * [!](%23/%21)
 * [!@#$%^&*()_+](%23/%21%40%23%24%25%5E%26%E2%88%97%28%29_%2B)
@@ -557,6 +557,7 @@ Make sure to see [contributing.md](/contributing.md) for instructions on contrib
 * [MATLAB 1.0](m/MATLAB%201.0.m)
 * [MATLAB](m/MATLAB.m)
 * [MaxScript](m/MaxScript.ms)
+* [Maxima](m/Maxima.max)
 * [Mel](m/Mel.mel)
 * [MemeAssembly](m/MemeAssembly.memeasm)
 * [Meq](m/Meq.meq)