doc: select titles of user tutorials

docs/user/tutorial/ARITHMETIC_OPERATIONS.md

@@ -0,0 +1,3 @@
+# Arithmetic Operations
+
+Umut to do: #312

docs/user/tutorial/FIRST_TUTORIAL.md

@@ -1,5 +0,0 @@
-# First Tutorial
-
-Umut to do: #312
-
-

docs/user/tutorial/SECOND_TUTORIAL.md

@@ -1,3 +0,0 @@
-# Second Tutorial
-
-Umut to do: #313

docs/user/tutorial/TABLE_LOOKUP.md

@@ -1,3 +1,3 @@
-# Third Tutorial
+# Table Lookup
 
 Umut to do: #314

docs/user/tutorial/WORKING_WITH_FLOATING_POINTS.md

@@ -0,0 +1,3 @@
+# Working With Floating Points
+
+Umut to do: #313