Issue #1030970 by loominade: Fixed Terms description not allowed for translation because of its input format.

Issue #1223522: Fixed missing API functions i18n_string_array_merge(), i18n_string_update_context() from install scripts, added some update dependencies.

Issue #1217782 by fietserwin: Fixed Strings page: option 'Clean up left over strings' does not work.

Cleaning up and making reusable string translation forms. Reworking field translation forms, path was too long for the menu.

Issue #1214616: Improved translation sets to keep track of related ones when moving items from one to another.

Fixed permission issue with taxonomy tests (needs administer site configuration to change string settings)

Issue #1192332: Fixed Incorrect message on wrong Block translation. Other format handling issues for translation form.

Issue #1170850: Fixed switching default language changes source language. Added variable for source language.

Fixed issues with taxonomy translation, reimplementing with object translation and advanced caching.

Fixed issues with setting string value and language code not passed around. Added per-textgroup hidden debugging option

Improved field translations and string handling. String objects are passed around instead of complex data arrays.

Fixed issues with previous commits. Introduced some more overridable functions for object translation.

Issue #1185644: API improvements. Added some internal caching (properties) in i18n_string_object_wrapper. Added some more easily overridable method translate_properties().

Issue #1185644: API improvements. Added i18n_string_object() to handle strings. Adding better caching for strings.

Issue #1185644: API improvements. Reordered functions. Improved object translation with some static caching. Using object translation for i18n_contact.