lock corpus table to ensure noother import is running
better error message
formatting
stuff
Merged 'develop'.

Conflicts:
	annis-service/src/main/java/annis/administration/CorpusAdministration.java
use a background thread
extract zip file to a temporary location and perform import
allow to check the current running job and finished jobs (by their UUID)
actuall output the messages
restrict import to users with the specific rights
allow to list *all* currently running or pending imports
starting to work in an import web-GUI
do not delete imported relANNIS files but instead store them inside the ".annis/zip-imports/" folder
removing unused older import function and re-order new functions arguments in order to be in sync with the inner function
allow to status update mails on corpus import (command line)
fixes #142
also allow service to send status mails
refactoring locking in order to be treated differently for command line and for service
allow read operations while importing corpus
altering the foreign key constraint will block other read accesses
cleaning up logging and message order