added simple math and charts modules

vendor/andileco/eval-math/README.md

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+
+Composer/Packagist version of EvalMath by Miles Kaufman
+Copyright (C) 2005 Miles Kaufmann <http://www.twmagic.com/>
+NAME
+----
+    EvalMath - safely evaluate math expressions
+  
+DESCRIPTION
+-----------
+    Use the EvalMath class when you want to evaluate mathematical expressions 
+    from untrusted sources.  You can define your own variables and functions,
+    which are stored in the object.  Try it, it's fun!
+        
+SYNOPSIS
+--------
+    `$m = new EvalMath;`
+    
+    `// basic evaluation:`
+    `$result = $m->evaluate('2+2');`
+    
+    `// supports: order of operation; parentheses; negation; built-in functions`
+    `$result = $m->evaluate('-8(5/2)^2*(1-sqrt(4))-8');`
+    
+    `// create your own variables`
+    `$m->evaluate('a = e^(ln(pi))');`
+    
+    `// or functions`
+    `$m->evaluate('f(x,y) = x^2 + y^2 - 2x*y + 1');`
+    
+    `// and then use them`
+    `$result = $m->evaluate('3*f(42,a)');`
+    
+    `// use methods (calc functions)
+    `$m->evaluate('1+max(2,3)') // => 4`
+    `$m->evaluate('if(1=2, 2+2, 5+5') // => 10
+
+METHODS
+-------
+    `$m->evaluate($expr)`
+        Evaluates the expression and returns the result.  If an error occurs,
+        prints a warning and returns false.  If $expr is a function assignment,
+        returns true on success.
+    
+    `$m->e($expr)`
+        A synonym for $m->evaluate().
+    
+    `$m->vars()`
+        Returns an associative array of all user-defined variables and values.
+        
+    `$m->funcs()`
+        Returns an array of all user-defined functions.
+        
+CALC METHODS (CALC FUNCTIONS)
+-----------------------------
+
+- `max(n...,m)` returns one of given arguments with maximal value
+- `min(n...,m)` returns one of given arguments with minimal value
+- `if(expr, true_value, false_value)` (has a `iif` synonym) returns `true_value` of `false_value` depends of `expr` evaluation result
+- `round(n,m)` returns rounded n value with m precision
+
+CREATE YOUR OWN CUSTOM CALC METHODS (CALC FUNCTIONS)
+-----------------------------------------------
+    You can create custom classes, that implements custom calc methods.
+    
+TODO
+----
+- Improve documentation
+- Ability to add custom operators
+- More tests
+
+CREDITS AND COPYRIGHTS
+----------------------
+This software integrates several libraries and patches by:
+
+- Original EvalMath library, (C) 2005 Miles Kaufmann <http://www.twmagic.com/>
+- Modifications for 'calc functions' by Moodle, <https://github.com/moodle/moodle>
+- Composer/Packagist version, (C) Daniel Bojdo, <https://github.com/dbojdo>
+