[SystemInfo] Added missing symbols for the Desktop build

Crosswalk cannot load the SystemInfo library because these two destructors are
missing.
Fixed style nit
Merge pull request #248 from tmpsantos/empty_space

Fixed style nit
Merge pull request #247 from tmpsantos/fix_missing_symbols

[SystemInfo] Added missing symbols for the Desktop build
Bump version to 0.28
[Download] Fixed type mismache error
Merge pull request #249 from qjia7/fix_type_mismatch

[Download] Fixed type mismache error
Bump version to 0.29
[Application] Add Applicatin extension skeleton and getAppInfo/getAppsInfo support

The implementation is based on spec:
https://developer.tizen.org/dev-guide/2.2.0/org.tizen.web.device.apireference/tizen/application.html

The ApplicationInformation class retrieves the application information mainly
through pkgmgr-info APIs. To get current application ID, we get the Crosswalk
app ID from Runtime interface and translate to Tizen ApplicationId in extension
creation.
[Application] Add Application API example for getAppInfo/getAppsInfo

Application API needs to be run in an installed app context, so a manifest file
is also added.