Update change log and spec for wrt-plugins-tizen_0.4.28

Update change log and spec for wrt-plugins-tizen_0.4.28

[model] REDWOOD
[binary_type] PDA
[customer] OPEN

[Issue] N/A
[Problem] listener invalid filter check bug fix
[Cause] listener invalid filter check bug fix
[Solution] listener invalid filter check bug fix

[Issue#] N/A
[Problem] When getter api is called, get virual path.
[Cause] N/A
[Solution] modification.

[Issue] N/A
[Problem] sortMode checkroutine bug fix
[Cause] sortMode checkroutine bug fix
[Solution] sortMode checkroutine bug fix

[Issue#] N/A
[Problem] When destructing Reader Object, its sessions were closed. But real reader was alive. So its sessions also has to be alive.
[Cause] When destructing Reader Object, its sessions were closed
[Solution] Removed the code for closing sessions.

[Issue#] N/A
[Problem] DS listener manager unneeded.
[Cause] Introduction of global context manager.
[Solution] Use global context manager instead of listener manager.

[Issue] N/A
[Problem] remove assert on DBus connection
[Cause] remove assert on DBus connection
[Solution] remove assert on DBus connection

[Issue] N/A
[Problem] Crash when callback message is null.
[Cause] Push FW throw null message in unknown error
[Solution] Add a null checker

[Issue] N/A
[Problem] body_download_status is not set for draft email message
[Cause] add attachment after add message reset the body_download_status field
[Solution] retry set body_download_status

[Issue] N/A
[Problem] setScreenState API was not guarantee sync operation
[Cause] platform API was not sync operation
[Solution] wait until state was changing

[Issue#] N/A
[Problem] plugin loading time
[Cause] Symbol visibility
[Solution] Rearranged symbol visibility

[Issue#] N/A
[Problem] warning while compile
[Cause] visibility syntax were inserted wrong place
[Solution] move the visibility syntax before &

[team] WebAPI
[request] N/A
[horizontal_expansion] N/A