Hotfix indexing0.6.5

This pull is an attempt to integrate three related pull requests: #128, #135 and #155.

The following requisites should be kept in mind:
- Should be easy to run with another language besides English
- Cleaner scripts (e.g. using ```$OUTPUT``` instead of ```$DBPEDIA_WORKSPACE/data/output/$lang_i18n```)
- Relative paths also help to make it cleaner to read.
- English files should not be renamed to other languages (e.g. spanish or greek), so that the user does not get confused. This may require that they change their configuration files manually later, when no model is available for their language. But at least in this case they know that the file comes from another language.
- Have download.sh and index.sh configured by default for english, because the distro includes indexing.en.properties and server.en.properties only.
- Usage of ```bin/unicodeEscape.py``` should be explained, including why it needs to be used, which languages might need it, etc.

Not all of these things are finished. I am now testing the merge with another language. But while it is running, I thought I should try out some new things here. I have never done a collaborative review on github before, but I wanted to invite @rafaharo, @iavraam and @HaliN to give it a try with me.

Can you guys please start taking a look at the merge? We can have the discussions here in the issue tracker. You could send me fixes as pull requests to my branch "pablomendes/hotfix-indexing0.6.5". I will merge them in and this pull request should keep evolving, right?