Removed timeshift module.

 It has been replaced by generic timeshift at es_out level.
The only regressions I see is:
 - it is not (yet) possible to timeshift module that (wrongly) advertize
 pace control.
 - the new timeshift still uses too much memory (~20Mbytes per hour for DVB-T).

modules/access_filter/Modules.am

-SOURCES_access_filter_timeshift = timeshift.c
 SOURCES_access_filter_dump = dump.c
 SOURCES_access_filter_bandwidth = bandwidth.c
 
 libvlc_LTLIBRARIES += \
-	libaccess_filter_timeshift_plugin.la \
 	libaccess_filter_dump_plugin.la \
 	libaccess_filter_bandwidth_plugin.la \
 	$(NULL)