Adding download tab and download manager, ffmpeg in worker thread

client/store/downloads.js

@@ -0,0 +1,36 @@
+
+export const state = () => ({
+  downloads: []
+})
+
+export const getters = {
+  getDownloads: (state) => (audiobookId) => {
+    return state.downloads.filter(d => d.audiobookId === audiobookId)
+  }
+}
+
+export const actions = {
+
+}
+
+export const mutations = {
+  addUpdateDownload(state, download) {
+    // Remove older downloads of matching type
+    state.downloads = state.downloads.filter(d => {
+      if (d.id !== download.id && d.type === download.type) {
+        return false
+      }
+      return true
+    })
+
+    var index = state.downloads.findIndex(d => d.id === download.id)
+    if (index >= 0) {
+      state.downloads.splice(index, 1, download)
+    } else {
+      state.downloads.push(download)
+    }
+  },
+  removeDownload(state, download) {
+    state.downloads = state.downloads.filter(d => d.id !== download.id)
+  }
+}