Experimental implementation of "reload" action

# Reload input list with different sources
  seq 10 | fzf --bind 'ctrl-a:reload(seq 100),ctrl-b:reload(seq 1000)'

  # Reload as you type
  seq 10 | fzf --bind 'change:reload:seq {q}' --phony

  # Integration with ripgrep
  RG_PREFIX="rg --column --line-number --no-heading --color=always --smart-case "
  INITIAL_QUERY=""
  FZF_DEFAULT_COMMAND="$RG_PREFIX '$INITIAL_QUERY'" \
    fzf --bind "change:reload:$RG_PREFIX {q} || true" \
        --ansi --phony --query "$INITIAL_QUERY"

Close #751
Close #965
Close #974
Close #1736
Related #1723

src/chunklist.go

@@ -64,6 +64,13 @@ func (cl *ChunkList) Push(data []byte) bool {
 	return ret
 }
 
+// Clear clears the data
+func (cl *ChunkList) Clear() {
+	cl.mutex.Lock()
+	cl.chunks = nil
+	cl.mutex.Unlock()
+}
+
 // Snapshot returns immutable snapshot of the ChunkList
 func (cl *ChunkList) Snapshot() ([]*Chunk, int) {
 	cl.mutex.Lock()