blocks: New block to convert streams to tagged streams
filter-based block tree search
Add 'Find Blocks' action and auto-hide search entry box
Removed the 'Add' button. Who used that anyway?
wxgui: ensure flowgraph shutdown before app exit

Also updates qtgui
Merge remote-tracking branch 'skoslowski/search_block_tree'
Allow variable vlen in GRC generated hier blocks
Merge branch 'maint'