README: Modify IoTivity README
To clarity the building steps, modify IoTivity README.
# IoTivity
IoTivity is an open source software framework enabling seamless device-to-device and device-to-cloud connectivity to address the emerging needs of the Internet of Things.
-
-Official page: https://www.iotivity.org/
+Official page: [IoTivity](https://www.iotivity.org/)
## How to build with IoTivity
### Prerequisites
-You need to install scons to build Iotivity with TizenRT.
-Please refer to the following page to install scons.
+SCons is a mandatory package to build IoTivity. Install it as below:
+```bash
+sudo apt-get install scons
+```
+For more information refer to the [web site](http://www.scons.org/doc/production/HTML/scons-user.html#chap-build-install).
-http://www.scons.org/doc/production/HTML/scons-user.html#chap-build-install
+### How to enable IoTivity
+There are two methods to enable IoTivity. One is using a pre-set configuration(defconfig), the other is using menuconfig.
+As a default configuration, you can use the IoTivity defconfig. Otherwise, you should enable this function through menuconfig.
-### Build Iotivity
-Configure the build from $TIZENRT_BASEDIR/os/tools directory.
+#### Using pre-set configration
+Use the IoTivity configuration.
```bash
-cd os/tools
-./configure.sh artik053/iotivity
+~/TIZENRT_BASEDIR$ cd os/tools
+~/TIZENRT_BASEDIR/os/tools$ ./configure.sh <board>/iotivity
```
-
-Configuration can be modified through make menuconfig from $TIZENRT_BASEDIR/os.
-You can enable security and cloud features for IoTivity.
+#### Using menuconfig
+Configuration can be modified through 'make menuconfig' from $TIZENRT_BASEDIR/os.
```bash
-cd ..
-make menuconfig
+~/TIZENRT_BASEDIR$ cd os
+~/TIZENRT_BASEDIR/os$ make menuconfig
```
-
-Finally, initiate build by make from $TIZENRT_BASEDIR/os
+Select the 'enable / disable iotivity stack' in menuconfig.
+Also it is possible to enable security and cloud features for IoTivity.
```bash
-make
+-+-External Libraries
+ |
+ +-enable / disable iotivity stack
```
+
