core: adding gr_random_pdu message passing block

Conflicts:
	gnuradio-core/src/lib/general/CMakeLists.txt
	gnuradio-core/src/lib/general/general.i
Merge branch 'master' into next
core: gr_socket_pdu missing iostream
block: file_source_impl missing mutex include
core: removed redundant test settings
Merge branch 'maint'
Merge branch 'master' into next

Conflicts:
	gnuradio-core/src/python/gnuradio/gr/CMakeLists.txt
digital: made the demod examples clearer
grc: Fixed Bug #485 by gracefully exiting when user sets GR_DONT_LOAD_PREFS=1 GRC_BLOCKS_PATH=
wxgui: dead code removal and formatting cleanup
core: added operator == for tags
core: added remove_tag_item()
Merge branch 'maint'
wxgui: implement persistence without using glAccum
Merge branch 'master' into next
Merge remote-tracking branch 'mbant/demod_examples'
Merge remote-tracking branch 'mbant/fix485'
Merge remote-tracking branch 'mbant/equal_for_tags'
Merge branch 'master' into next

Conflicts:
	gr-digital/examples/demod/ber_simulation.grc
	gr-digital/examples/demod/digital_freq_lock.grc
	gr-digital/examples/demod/pam_sync.grc
	gr-digital/examples/demod/pam_timing.grc
digital: fixed up examples for the updated location of blocks.