Added a .tl file tokenizer and parser

A TLObject class has been added, as well as a method for tokenizen .tl files.
A TLObject can be created by simply calling `TLObject.from_tl(tl_line)`,
  this will tokenize the .tl line and return a new TLObject with all
  the required properties extracted.
Also added another method to load .tl files and yield TLObjects, including
  a SourceBuilder that can be later used to generate Python code.

parser/tl_parser.py

@@ -0,0 +1,30 @@
+import re
+from tl.tlobject import TLObject
+
+
+class TLParser:
+    """Class used to parse .tl files"""
+
+    @staticmethod
+    def parse_file(file_path):
+        """This method yields TLObjects from a given .tl file"""
+
+        with open(file_path, encoding='utf-8') as file:
+            # Start by assuming that the next found line won't be a function (and will hence be a type)
+            is_function = False
+
+            # Read all the lines from the .tl file
+            for line in file:
+                line = line.strip()
+
+                # Ensure that the line is not a comment
+                if line and not line.startswith('//'):
+
+                    # Check whether the line is a type change (types ⋄ functions) or not
+                    match = re.match('---(\w+)---', line)
+                    if match:
+                        following_types = match.group(1)
+                        is_function = following_types == 'functions'
+
+                    else:
+                        yield TLObject.from_tl(line, is_function)