Add ability to set a LIBJS_PATH when compiling

README.md

 to just directly insert the contents of `<filename>` into the file. -Instead of wasting the compilers energy checking for circular sources, you have two options, to not be so stupid or wait for the call stack to overflow.- Yay now the compiler protects you against circular sources, or sourcing the same file more than once by skipping these when it encounters them, this means that order is now important. Although it always was.
 
 The compiler runs like `node compiler.js file.mc` where `file.mc` is the file you wish to compile, and this will produce a
-`file.mc.js` which requires the `libjs` directory to be present in the same directory when running for now at least.
+`file.mc.js` which requires the `libjs` directory to be present in the same directory when running or for the environment variable
+`LIBJS_PATH` to have been set whilst compiling.
 
 Functions and variables are in different scopes, so variables can have the same names as functions - even builtins -
 thus making `(assign assign 5)` a totally okay thing to do. However note that builtins and defined functions are in the same scope no matter what and attempting to define a function with the same name as a builtin will not work properly.

compiler.js

   switch (node.type) {
     case 'Prog':
       let program = node.body.map(generator)
-      program.unshift('var _ = require("./libjs/stdlib.js")(this)')
+      program.unshift('var _ = require("' + libjsPath + '/stdlib.js")(this)')
       return program.join('\n')
       break
     case 'Statement':
         if (node.callee.name.match('include')) {
           // Include is a special function and we will write the generation ourselves
           return node.args.map((arg) => {
-            let lib = './libjs/' + arg.value + '.js'
+            let lib = libjsPath + '/' + arg.value + '.js'
             return ('var _' + arg.value + ' = require("' + lib + '")(this)')
           }).join("\n")
         } else {
 
 }
 
+let libjsPath = process.env['LIBJS_PATH']
 const fileNameIn = process.argv[2]
 const fileNameOut = fileNameIn + '.js'
 const myInput = fs.readFileSync(process.argv[2], { encoding: 'utf-8' })
 
+if (libjsPath === '') {
+  libjsPath = './libjs'
+}
 const preProcessedInput = preprocess(fileNameIn, myInput) // Run the preprocessor to evaluate any `source's
 const myTokens = tokenizer(preProcessedInput) // Convert our input into individual tokens
 const parsedTree = parser(myTokens) // Convert these tokens into a syntax tree