introduce the "SchemeFixer" that fixes the database scheme on demand at import time
allow to pass an "alias" parameter to the import functions (not used yet)
use alias name at import and change explicit deletion of rows that reference corpus.id to an implicit deletion
Merged 'develop'.

Conflicts:
	annis-kickstarter/src/main/java/de/hu_berlin/german/korpling/annis/kickstarter/ImportDialog.java
	annis-service/src/main/java/annis/administration/CorpusAdministration.java
	annis-service/src/main/java/annis/service/internal/ImportWorker.java
introducing an alias REST function to query corpora by their alias names
use more general REST function to get the corpus information (AnnisCorpus object) and for a corpus and/or alias
map names using the service and re-activating the actual code to select the corpora from the fragment
allow to use "alias" also when importing using the service
allow to delete corpora by their name (and not only ID)
allow to import multiple corpora from one zip file in service
we check if a corpus was imported already before we get to this code, we should always overwrite it since it might be old stuff that was never deleted
wrong logic
do not output error when resolver_vis_map table does not exist in relannis import folder
nicer output messages, all messages now have a single parent "messages" element
also call scheme fixer after initializaing database
multiple enhancements for importing multiple corpora and using alias names

- alias can point to several corpora
- adminstration service allows to import several corpora and to set an alias name (fixes #189)
- some smaller improvements in the import process
- introducing \"scheme fixer\" concept where some tables etc. could be added on demand at import (thus minimizing the number of times people have to upgrade their database after a new release)
refactoring the LoginServlet to a RequestHandler in order to have the Vaadin Session available
More user friendly message when postgres is not available when importing
corpora.
Decode corpus names in the url when fetching corpus.properties via rest api.
Add mapping from a single corpus id to the corpus name.