Fix style and conditions
Put Select2 breadcrumbs CSS customizations in a separate stylesheet

This will allow keeping select2.css closer to upstream one.
Adjust custom Pootle colors in CSS for Select2
Apply Select2 to all selects in Pootle

This should fix bug #2608.

Added js-select2 class to all selects in order to apply Select2.
The width styling is applied using CSS.
Added placeholders with help for multiple selects.
Hide help for multiple select in order to avoid misleading users.
Docs: API specs updates

[ci skip]
Use em-dash
Bump up Django version following bd1df98
Python 2.5 is the minimum; be explicit about Django versions.
Modify Travis testing to reflect Pootle 2.5.1 requirements:

Python 2.5 - 2.7
Django 1.4 - 1.4.5

also add some forward looking excludes to the matrix
always notify on failure (on master & release branches, at least)
Python 2.5 relative import * fix

For some reason 2.5 is fussier about relative imports than later versions
Use absolute imports instead to keep it happy
Document Django requirement for Pootle 2.5.1 in changelog
Document VCS_DIRECTORY and split in changelog for 2.5.0
Documentation grammar fix
precommit hooks return an array of files
preupdate hook returns a new file

only accepts one path not an array of paths

refs #2682
run the postupdate hooks before updating the stores

this allows the hook to modify the new data
call precommit and postcommit hooks when adding files
add "pretemplateupdate" hook

This hook is called before updating a file from the template.
The hook can prevent the updating with a False return value.
comment typo
doc typos and updates

preupdate return is treated as a filename, not an array of filenames