Added displayPackageInstallDialog()

Import/Export Settings needs to point out that fileread/filewrite module
is required. They both make now use of the displayPackageInstallDialog()
method.
homepage: Added HTML anchor for donate section
main: Added Donate button
DialogUtil: Removed unnecessary dialog.dismiss()
transport-xmpp: New master JIDs as textEmailAddress

If a new master JID is added, it should also have
android:inputType="textEmailAddress". This is done by ORing
TYPE_CLASS_TEXT with TYPE_TEXT_VARIATION_EMAIL_ADDRESS
homepage: updated flattr URL
transport-xmpp: added pingServer button
transport-xmpp: new eclipse classpath
transport-xmpp: removed unused registerAccount method
Removed focusableInTouchMode from all Buttons