FIX 7906 Regression: GridFieldConfig_RelationEditor: Removing relation deletes data object
Added composer.json
Merge pull request #877 from UndefinedOffset/3.0

FIX 7906 Regression: GridFieldConfig_RelationEditor: Removing relation d...
Adding changelog for 3.0.3-rc1
adding 3.0.3-rc1 to changelog index
Removed 'from-source' documentation
Added composer documentation for using project forks.
Tidy up formatting of composer docs.
Added docs about composer branch names and forks.
Fixed sapphiredocs references
Upgrade jQuery UI to 1.9

- Fixed jQuery.tabs remote tabs loading behaviour (see http://forum.jquery.com/topic/tabs-api-redesign)
Removed usage of deprecated jQuery UI 1.9 features

See http://jqueryui.com/upgrade-guide/1.9 for details.
Fixes fade effect on changing toplevel tabs
(semantics for "show" option in $.tabs() changed).
Adding additional test for populateDefaults() in DataObjectTest
Adding ability to translate "Edit" text in GridFieldEditButton
Adding title to CMSProfileController so translations get default
Updating default en.yml translations
Fixing performance of DataObject::custom_database_fields()

On sites with lots of modules, and pages with plenty of database
queries, DataObject::custom_database_fields() can be called
thousands of times, and slow down page render times. This fixes
it so the fields are cached by class in a static variable, and
are cleared when reset() is called on the DataObject.
Merge pull request #936 from halkyon/custom_database_fields_cache

Fixing performance of DataObject::custom_database_fields()
Note about backtick in entwine shortcuts
Improve performance of DataObject::db() with caching

In a usual CMS request, DataObject::db() is called potentially
thousands of times, calling Config::get() constantly for the same
uninherited statics, which is slow. This improves performance
by caching those into DataObject::$_cache_db