Added regex to identify API section of readme

Author: Subhash3

nicedoc/regex_utils.py

@@ -12,3 +12,18 @@
 
 # Given a python file, extracts all the camelcased variable/methods/functions.
 EXTRACT_CAMEL = r"(^(?!\s*print.*).*)((\b[a-z]+)(([A-Z]+[a-z]+)+?)\b)"
+
+# Splits the readme contents based on the API section.
+# This assumes that API is a <h2> header, i.e ## API, and is followed by a <h3> Todo (### Todo).
+# Parts                 Captured Group
+# Everything that
+# comes before the            1
+# API section
+#
+# API section along
+# with its contents           2
+#
+#  Everything that
+# comes after the             3
+# API section
+SPLIT_README_BY_API = r"^(?<![.\n])(.*\s*)*?(## API(.*\s*)*?)(###\sTodo(.*\s*)*)"