Simplify Unix Path2

Simplify a give path

**Input: ** String. Unix path.

**Output: ** String. Unix path.

**Example:**

simplify_path('/a/') == '/a' simplify_path('/a/b') == '/a/b' simplify_path('/a//b/c') == '/a/b/c' simplify_path('/a/b/./ci') == '/a/b/ci' simplify_path('/a/b/../c') == '/a/c'