remove installation guide from README

the guide which was in the README was to big
moved the missing parts into the wiki and
remove the text
set ontology_id of translated sentence correctly

The ontology_id of translated sentence should
equal the ontology_id of the underlying sentence
and not the origin of the mapping.

This is because there could be multiple mappings
without a sentence-definition in between.
add migration to reset translated ontology_id

For TranslatedSentences the ontology_id should refer
to the origin sentences ontology_id (it should
basically be a shortcut).

The migration will take care of that. However
there is no reversal for this particular migration
as the erroneous data is 'lost'.
rename method remote? to mirror?
Merge pull request #979 from ontohub/963-rename_remote_to_mirror

rename method remote? to mirror?
Merge pull request #976 from ontohub/936-readjust_origin_of_sentences

936 readjust origin of sentences
updated general information about ontohub
handle non-existence during timeout

If an ontology version can't be found it probably does not exist, so we
can't timeout on it.
declare queues for workers explicitly.
let god start sequential worker(s).
Merge pull request #986 from ontohub/76-better_documentation

76 better documentation
update usage of ontology-united with vars.
Merge pull request #980 from ontohub/fix_update_the_usage_of_ontology_united

update usage of ontology-united with vars.
change determination of final state for timeout.
Merge pull request #994 from ontohub/fix_by_explicitly_declaring_queues

declare queues for workers explicitly.
Merge pull request #995 from ontohub/fix_working_on_sequential_queue

let god start sequential worker(s).
Merge pull request #993 from ontohub/899-do_not_fail_on_non_existence

899 do not fail on non existence
move db cleaner config to separate file
replace rake task db:purge with db:migrate:clean
remove ontology file extensions stubs