Issue #1738330 by k4v, das-peter, jsbalsera, bforchhammer, Schnitzel: confusing Language negotiation when accessing /.

- Patch #322995 by Schnitzel, c31ck, webflo, penyaskito: provide a distinct administration user interface language option.

Issue #1739994 by pp, das-peter, Gábor Hojtsy: Use the Language class universally instead of stdObj instances.

Issue #1280996 by tarmstrong, vasi1186, fastangel, dawehner, tobiasb: New language_select() element type for form API.

Using the language_manager wrapper function to return a language whether or not we're in the requet scope

- Patch #1290694 by hefox, tlattimore, c4rl, chx, tim.plunkett, tstoeckler, msonnabaum: provide consistency for attributes and classes arrays provided by template_preprocess().

Issue #1471432 by Gábor Hojtsy, vasi1186, tobiasb, kalman.hosszu, Schnitzel, nod_, pixelite, dawehner: Rework language_list(), let people use more special languages.

- Patch #1510686 by cosmicdreams, vasi1186, webflo, disasm: replace remaining references to global () with drupal_container().

- Patch #1627208 by vasi1186: make language_list() and language_default() return instances of Language.

Issue #1443202 by TravisCarden, tim.plunkett, xjm: Make sure hook_preprocess documentation points to real funcions

- Patch #1183208 by effulgentsia, Niklas Fiekas, katbailey, no_commit_credit, catch: remove variable_get()('clean_url()') and switch to index.php/path pattern for dirty URL support.

- Patch  #1468930 by dawehner, Gábor Hojtsy, plach, das-peter, fubhy: clean up and move the code for the negotiation functionality from locale module to language module.

- Patch #1414314 by Gábor Hojtsy, tstoeckler: make node and path depend on language module only for language support, get rid of locale_language_name().

- Patch #1405604 by aspilicious: Fixed RTL stylesheets don't get triggered when locale isn't enabled.

Issue #1301040 by Gábor Hojtsy: Move language listing functionality from locale.module to a new language.module.