Improve "Unchanged String" view
* Fixed styling of first row of results
* Make column headers visible even when a component is filtered
* Added dir and lang attributes to rows

"Unchanged strings" model:
* Don't try to compare non existing strings

Fixed undefined var $target_string2 warning in views/results_entities.php
Use htmlentities on search strings before displaying them, improve CSS for no results
Issue #400: add github pushes integration hook

Action needed on the beta server after this push:
- add secret key in config.ini
- create a file web/github_log.txt with the user www-data:www-data

We don't keep the log file in app/logs/ because we want to be able to access the date of the last update from GitHub into the browser
Merge pull request #401 from pascalchevrel/issue400-update_beta_site_with_github_pushes

Issue #400: add github pushes integration hook
Merge pull request #398 from flodolo/issue397

Encode HTML on search string before display, improve CSS without results
Merge pull request #395 from flodolo/fix_unchanged

Improve "Unchanged String" view
Generate list of all supported repos from external sources, load supported locales from list
Use Aurora as default search
Launch setup.sh to the list of actions triggered by Github hook
Merge pull request #405 from pascalchevrel/add_setupsh_script_to_github_hook

Launch setup.sh to the list of actions triggered by Github hook
Merge pull request #404 from flodolo/update_repos

Load list of all repositories dynamically, get list of locales from txt files, use Aurora as default
force archlinux to use python2
Merge pull request #402 from SkySymbol/archlinux-transvision

Archlinux transvision