tutorial typos fixed (bug 379)

doc/tutorial/building-topologies.texi

@@ -63,7 +63,7 @@ off of the right side.  Notice that this is the default network topology
 since you can actually vary the number of nodes created on the LAN.  If you
 set nCsma to one, there will be a total of two nodes on the LAN (CSMA 
 channel) --- one required node and one ``extra'' node.  By default there are
-thee ``extra'' nodes as seen below:
+three ``extra'' nodes as seen below:
 
 @verbatim
 // Default Network Topology
@@ -589,7 +589,7 @@ number of nodes created on the wired and wireless networks.  Just as in the
 number of ``extra'' CSMA nodes.  Similarly, you can set @code{nWifi} to 
 control how many @code{STA} (station) nodes are created in the simulation.
 There will always be one @code{AP} (access point) node on the wireless 
-network.  By default there are thee ``extra'' CSMA nodes and three wireless 
+network.  By default there are three ``extra'' CSMA nodes and three wireless 
 @code{STA} nodes.
 
 The code begins by loading module include files just as was done in the

doc/tutorial/conceptual-overview.texi

@@ -681,7 +681,7 @@ When we previously called the methods,
 @end verbatim
 
 we actually scheduled events in the simulator at 1.0 seconds, 2.0 seconds and
-10.0 seconds.  When @code{Simulator::Run} is called, the ssytem will begin 
+10.0 seconds.  When @code{Simulator::Run} is called, the system will begin 
 looking through the list of scheduled events and executing them.  First it 
 will run the event at 1.0 seconds, which will enable the echo server 
 application.  Then it will run the event scheduled for t=2.0 seconds which 

doc/tutorial/tweaking.texi

@@ -180,7 +180,7 @@ actually a class name, and there is a single colon there instead of a double
 colon to remind you in a relatively subtle way to conceptually separate the 
 logging component name from the class name.
 
-It turns out that in come cases, it can be hard to determine which method
+It turns out that in some cases, it can be hard to determine which method
 actually generates a log message.  If you look in the text above, you may
 wonder where the string ``@code{Received 1024 bytes from 10.1.1.2}'' comes
 from.  You can resolve this by ORing the @code{prefix_func} level into the
@@ -625,7 +625,7 @@ need to hook the value into the parser.  We do this by adding a call to
 start with the following code,
 
 @verbatim
-    int
+  int
   main (int argc, char *argv[])
   {
     uint32_t nPackets = 1;