conversations: touch-ups for text message items

...p/src/main/java/cx/ring/adapters/ConversationAdapter.java

ring-android/app/src/main/java/cx/ring/utils/UiUpdater.java

...p/src/main/java/cx/ring/views/ConversationViewHolder.java

ring-android/app/src/main/res/drawable/textmsg_bg_in.xml

...android/app/src/main/res/drawable/textmsg_bg_in_first.xml

...-android/app/src/main/res/drawable/textmsg_bg_in_last.xml

...ndroid/app/src/main/res/drawable/textmsg_bg_in_middle.xml

ring-android/app/src/main/res/drawable/textmsg_bg_out.xml

...ndroid/app/src/main/res/drawable/textmsg_bg_out_first.xml

...android/app/src/main/res/drawable/textmsg_bg_out_last.xml

...droid/app/src/main/res/drawable/textmsg_bg_out_middle.xml

ring-android/app/src/main/res/layout/item_conv_image.xml

ring-android/app/src/main/res/layout/item_conv_msg_me.xml

ring-android/app/src/main/res/layout/item_conv_msg_peer.xml

ring-android/app/src/main/res/values/dimens.xml

...main/java/cx/ring/conversation/ConversationPresenter.java

...ibringclient/src/main/java/cx/ring/model/Interaction.java