Issue #2195183 by cleaver, zopa, elgordogrande, sandykadam, jhodgdon, joachim, Eda: document Batch API callbacks as callback implementations

Issue #2392221 by joegraduate, er.pushpinderrana, zealfire, ClientGuy: install_run_task() and install_tasks() don't document the task structure

Issue #1760330 by s.Daniel, David_Rothstein, jfhovinne: Hide vulnerable drupal install.php sites from search engines.

Issue #1727430 by tedbow, webchick, fubhy | amontero: Added 'exclusive' flag to install profiles to auto-select them during installation.

Issue #1198398 by jm@bellcom.dk, AllRob: Fixed Timezone selected on install not correctly saved to admin user account.

Issue #655190 by dealancer: Fixed Allow hook_install_tasks() to be called from a profile's .install file (or document that it can't be).

Issue #212284 by Damien Tournoud, alexanderpas, dww: Fixed security check in 'configure' stage not compatible with overriding variables: site_name() and site_mail().

Issue #951644 by catch, David_Rothstein, aschiwi, xjm: Fixed Requirement warnings (e.g. for PHP memory limit) are not shown on install or update unless there is a requirement error also.

#1007488 by Gábor Hojtsy, plach, droplet: Fixed Drupal cannot be installed in a non-predefined language

#534556 by karschp, coltrane, Bojhan, David_Rothstein: Fix double appearance of the settings.php message in the installer

#346494 by hswong3i, Pancho, Dave Reid, duellj, dalin: Fixed DB drivers need to be able to change the configure database form during install

- Patch #689954 by Mark Trapp: installation complete message doesn't conform to Drupal path conventions.

#938470 by Kevin Hankens: Change error about file permissions on settings.php during install to warning instead.

- Patch #818374 by Damien Tournoud, ksenzee, Dave Reid: add a requirements check error if PECL PDO is being used.

- Patch #140783 by sun, chx, effulgentsia, David_Rothstein, webchick: a select list without #default_value() always passes form validation.

#882164 follow-up by Gábor Hojtsy, reglogge: Further clarifications to localization install instructions.

#418302 follow-up by David_Rothstein, reglogge, dww: Deal with obscure edge case when attempting to create settings.php during installation.

#882164 by aschiwi, Gábor Hojtsy, David_Rothstein, reglogge, et al: Fix the 'install from another language' instructions so that they actually work.

- Patch #910572 by sun, David_Rothstein: command line installations are broken (programmatic form submissions don't need a theme?).

#418302 by David_Rothstein, dww, reglogge, and lots and lots of other people: Copy default.settings.php to settings.php during install if webserver owns files. Eliminates 'red error of death' during install for most shared hosting set-ups.

#898654 by chx, Damien Tournoud, alex_b: Fixed Required modules not installed before optional modules.

- Patch #323477 by justinrandell, boombatower, tstoeckler, Damien Tournoud: increase simpletest speed by running on a simplified profile.