Remove redundant code hook in `onViewToolbarsPopupShowing` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser.addTab` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser.moveTabForward` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser.moveTabBackward` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser.moveTabToEnd` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser.moveTabToStart` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser.moveTabForward` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser.moveTabBackward` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `PlacesCommandHook.bookmarkPage` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gBrowser._beginRemoveTab` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove `extensions.tabutils.closeLastWindowWithLastTab` preference

This preference does nothing and `browser.tabs.closeWindowWithLastTab`
should be used instead.
Remove redundant code hook in `gBrowser._endRemoveTab` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Remove redundant code hook in `gURLBar.handleCommand` function

Found using warning "TU_hookFunc: nothing was replaced" (dd33b13).
Options: Disable "Close Tab button" list if checkbox is unchecked
Merge branch 'dev'
README: Update project name
README: Add information about v1.2.0 release
Release v1.2.0