[DLNA] Add sort options for MediaServer example

This patch adds sorting options to mediaserver.html
[Tizen] Fix for File.length and File.fileSize properties

File.length should be undefined for files and defined for directories,
while fileSize should be only available for regular files.
[Application] Add application context, kill, launch and app info events support

The supported APIs are listed below:
Application,
ApplicationContext,
ApplicationManager.getCurrentApplication,
ApplicationManager.getAppContext/getAppsContext,
ApplicationManager.kill/launch,
ApplicationManager.addAppInfoEventListener/removeAppInfoEventListener

As we runs extension process logic on launcher now, the AUL related APIs can be
directly called in this extension.
The C++ Application class will represent current running application and owned
by ApplicationExtension. The ApplicationManager class will provide methods to
manipulate other applications and listening to app info events.
Merge pull request #286 from seanlong/app_dev

[Application] Add application context, kill, launch and events support
[Tizen] Content API - Part 3

Added support for Tizen filters (AttributeFilter only). The rest (Range and Composite) are coming later.

Added also support for media type specific attributes for audio, video and image types.

Changed some types to more convenient ones f.ex timestamp to string.

Added filtering features to examples/content.html test page.
Merge pull request #287 from alexshalamov/fix_file_attributes

[Tizen] Fix for File.length and File.fileSize properties
Merge pull request #278 from poussa/content-3

[Tizen] Content API - Part 3
Bump version to 0.49
[Application] Add current application exit/hide support

The supported APIs are listed below:
Application.hide/exit

The implementation leverages running application object exported by the runtime
process on the DBus session. The "Terminate" and "Exit" methods of it only
permit the launcher process to access.

Supplement Application example for new added APIs are also added.
Merge pull request #289 from seanlong/app_dev

[Application] Add current app exit/hide support
Bump version to 0.50
[Tizen] Don't throw exception when empty files are read

This patch removes check that throws exception when empty file is read.
Merge pull request #293 from alexshalamov/fix_read_empty_file

[Tizen] Don't throw exception when empty files are read
Bump version to 0.51
[Tizen] Move MediaServer dbus objects to worker thread

This patch adds new worker thread with g_main_loop for async
dbus call processing.
Merge pull request #262 from alexshalamov/add_sort_options

[DLNA] Add sort options for MediaServer example
Bump version to 0.52
[Content] Update instance counter in anycase

Update the instance counter in any case and not just when connected sucesfully
to the database. Otherwise, the assert will cause crash in dtor later on.

BUG=https://crosswalk-project.org/jira/browse/XWALK-1599
Merge pull request #294 from poussa/xwalk-1599

[Content] Update instance counter in anycase
[Application] Add application metadata support

Below APIs are added:
ApplicationMetaData
ApplicationManager.getAppMetaData

Application metadata is specified in config.xml and can be readonly
accessed by both native and web applications.

BUG=XWALK-1610