Allow selecting buffers

...chku/quasseldroid_ng/ui/chat/buffers/BufferListAdapter.kt

...asseldroid_ng/ui/chat/buffers/BufferViewConfigFragment.kt

app/src/main/res/drawable-v21/bg_menuitem_dark.xml

app/src/main/res/drawable-v21/bg_menuitem_light.xml

app/src/main/res/drawable/bg_menuitem_dark.xml

app/src/main/res/drawable/bg_menuitem_light.xml

app/src/main/res/layout/widget_buffer.xml

app/src/main/res/layout/widget_network.xml

app/src/main/res/values/attrs.xml

app/src/main/res/values/colors.xml

app/src/main/res/values/themes_base.xml