Improved channel list

...java/de/kuschku/quasseldroid_ng/service/QuasselService.kt

...a/de/kuschku/quasseldroid_ng/ui/chat/BufferListAdapter.kt

...schku/quasseldroid_ng/ui/chat/BufferViewConfigFragment.kt

...a/de/kuschku/quasseldroid_ng/util/helper/ContextHelper.kt

.../kuschku/quasseldroid_ng/util/helper/LiveDataZipHelper.kt

...ava/de/kuschku/quasseldroid_ng/util/helper/ThemeHelper.kt

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

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

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

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

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

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

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

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

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

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

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

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

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

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