Minor layout changes: padding and text size.

briar-android/res/values/strings.xml

...src/net/sf/briar/android/contact/ContactListActivity.java

.../src/net/sf/briar/android/invitation/BluetoothWidget.java

.../src/net/sf/briar/android/invitation/CodeEntryWidget.java

.../net/sf/briar/android/invitation/CodesDoNotMatchView.java

...net/sf/briar/android/invitation/ConfirmationCodeView.java

...net/sf/briar/android/invitation/ConnectionFailedView.java

...d/src/net/sf/briar/android/invitation/ConnectionView.java

...src/net/sf/briar/android/invitation/ContactAddedView.java

...c/net/sf/briar/android/invitation/InvitationCodeView.java

...src/net/sf/briar/android/invitation/NetworkSetupView.java

...c/net/sf/briar/android/invitation/WaitForContactView.java

...droid/src/net/sf/briar/android/invitation/WifiWidget.java

...c/net/sf/briar/android/messages/ConversationActivity.java

...t/sf/briar/android/messages/ConversationListActivity.java

...rc/net/sf/briar/android/messages/ReadMessageActivity.java

...c/net/sf/briar/android/messages/WriteMessageActivity.java