Fix memory leak by unrefing the GdkPixBuf

Restore svn history for the lua modules (For future reference [21376]: modules/misc/lua: Share some code between the modules that uses lua and put them in a single module.)

- Do not refer to bogus TTL values

There is no way at the moment to know if a file is audio only

Even then rtp.c is quite big...

freetype: balance vlc_object_find() and vlc_object_release(), otherwise object is leaked (refcount > 0 on quit):

Fix some warnings

Add new module_FindName function to find a module when given it's name. Use this to fix the qt interface extended panel (video filters).
Change module_Exists to take the module name (and not short name) as parameter. Update the only known use of that function acordingly.

Enforce access to input_item_t through input_item_{G,S}et*()
Unlock mutexes before calling these functions
Free strings returned by input_item_Get*()

New functions added:

char * input_item_GetURI( input_item_t  * )
void input_item_SetURI( input_item_t * , char * )

mtime_t input_item_GetDuration( input_item_t * )
void input_item_SetDuration( input_item_t * , mtime_t )

to access input_item_t->psz_uri and input_item_t->i_duration

Revert [21140] which broke the extend panels in Qt4 + add a comment so this doesn't happen again. (Please test changes before commiting ... thanks)