Finish moving lmathlib, removing the C file (#14)

* Finish moving lmathlib, removing the C file

* cargo fmt

Author: bobtfish

Cargo.lock

@@ -11,6 +11,7 @@ bench = false
 
 [dependencies]
 libc = "0.2"
+rand = "0.8.5"
 
 [build-dependencies]
 cc = "1.0"

Cargo.toml

@@ -16,7 +16,6 @@ fn main() {
         .file("build/lcorolib.c")
         .file("build/ldblib.c")
         .file("build/liolib.c")
-        .file("build/lmathlib.c")
         .file("build/loslib.c")
         .file("build/lstrlib.c")
         .file("build/lua.c")