Add very preliminary GF-webservice-based GF engine

to replace the JPGF-based GF engine in the future.
The current version is not yet functional,
only the basic structure is there.

The GF webservice is accessed via lib/gf-java.jar.

Also add lib/json_simple-1.1.jar (which is required at runtime by lib/gf-java.jar).

Also add lib/guava-11.0.1.jar to simplify implementing
e.g. string and collection operations.
Fix completion handling

The GF webservice-based GF engine is now functional and
seems to have the same functionality as the previous JPGF-based engine.
Use ACE-in-GF instead of Foods + minor fixes

The PGF of ACE-in-GF can be downloaded from

https://github.com/Attempto/ACE-in-GF
Serialize into tree + languages from PGF

Every wiki sentence is now serialized as its abstract tree.
Loading the wiki now only involves linearization.

The information about which concrete languages are present
now comes from the PGF. In `web.xml` one still needs to
specify the language-to-URL mappings though.
Add details generation for GFDeclaration

Most importantly the details page lists all the translations.
Minor cleanup
Add support for alignment diagram (under Details)
Update to the latest gf-java.jar
Add abstrtree and parsetree to sentence details
Add a separate servlet for the GF Geo grammar
Add the list of languages to the side column

Note that the automatically created links to the
different language pages (e.g. http://localhost:9077/mgl/CommandsEng/)
expect a certain naming convention in the web.xml
(ontology = mgl, language = CommandsEng), and an existing servlet
mapping.
Add an HTML-page listing all GF-based wikis

for a better overview.
Also add the missing servlet mappings.
Modularize web.xml + add GF webeditor link to Wiki

Using &entities; in web.xml, not sure if it is supported everywhere.
Make servlet mappings unambiguous
Make storage directory names unambiguous
Sort sidepanel languages alphabetically +

minor updates to GF wiki servlets and link pages.
Demonstrate the login mechanism

  - Foods: 2 language-specific logins (for Afr and Dut)
  - Numerals: 1 wiki-specific login
Update the list of available grammars
Add support for start_cat-parameter in web.xml

Otherwise did not get the new ACE-in-GF grammar to work,
because for some reason its start category is not automatically
found from the PGF.
Now storing all the trees i.e. the ambiguous parse

The Details-view offers a preliminary display
of the ambiguity.