[demo] add system info demo

The added demo packages is:
   tizen-extensions-crosswalk-system-info-demo-${version}-${release}.${arch}.rpm
Install the package with `pkgcmd`, like:
   $ pkgcmd -i -t rpm -p tizen-extensions-crosswalk-system-info-demo-0.2-0.i586.rpm -q
More information about demos at commit `1ed2d38`.
Merge pull request #109 from legendlee1314/newdemos

[demo] add system info demo
[SystemInfo] Fix read-only properties not covered support
Merge pull request #122 from legendlee1314/master

[SystemInfo] Fix read-only properties not covered support
Value of WebAPIException should be number

For code like:
tizen.WebAPIException(tizen.WebAPIException.TYPE_MISMATCH_ERR)

the tizen.WebAPIException.TYPE_MISMATCH_ERR should be number, so that
the WebAPIException can be correctly constructed.
Merge pull request #124 from deqing/fix-tizen-exception

Value of WebAPIException should be number
[SystemInfo] Add apn support in cellular
[SystemInfo] Fixed type mismatch error in cellular
[SystemInfo] Capitalize abbreviation in function name
Merge pull request #118 from qjia7/mymaster

[SystemInfo] Implement the missed property in cellular
Fix time examples
Use correct validation on time examples
Fix error codes on tizen test examples

Error codes are following tizen_api.js and tizen.h
Fix notification examples

intentional exception now is using 'shouldThrow'
Merge pull request #127 from ricardotk/wip

Fix some examples
[SystemInfo] Use timeout_cb_id_ to identify listener on desktop
[SystemInfo][LOCALE] Use vconf on Tizen Mobile
Merge pull request #123 from fyraimar/master

[SystemInfo] Modify Locale API implements on Tizen Mobile and uniform API implements on Desktop
[SystemInfo] Add parameter type checking in js
Merge pull request #129 from qjia7/mymaster

[SystemInfo] Add parameter type checking in js