Updated titles

docs/source/input_api.rst

@@ -1,8 +1,8 @@
 .. _api:
 
-************************************
-Advanced Model Building (Python API)
-************************************
+**************************************
+Model Building - advanced (Python API)
+**************************************
 
 Introduction
 ============

docs/source/input_hash_cmds.rst

@@ -1,8 +1,8 @@
 .. _commands:
 
-******************************
-Model building (hash commands)
-******************************
+***************************************
+Model Building - simple (hash commands)
+***************************************
 
 An input file has to be supplied to gprMax which should contain all the necessary information to run a GPR model. The input file is an ASCII text file which can be prepared with any text editor or word-processing program. In the input file the hash character (``#``) is reserved and is used to denote the beginning of a command which will be passed to gprMax. The general syntax of commands is: