introduced std library tests (only regex for now) and a working _sre mixin, which is used by the module

test/completion/std.py

@@ -0,0 +1,20 @@
+"""
+std library stuff
+"""
+
+# -----------------
+# re
+# -----------------
+import re
+c = re.compile(r'a')
+#? int()
+c.match().start()
+
+#? int()
+re.match(r'a', 'a').start()
+
+#? int()
+next(re.finditer('a', 'a')).start()
+
+#? str()
+re.sub('a', 'a')