l10n_client 6.x-1.8

Was about time to cut this release. Includes a much-much better README, several JavaScript fixes, actual support for different text formats (i18nstrings module) and per-user settings to hide the l10n_client form.

Detailed changes since 6.x-1.7:

• #519146 by myself: backport of the bugfixes made while porting the module to Drupal 7
• #729350 by batigolix: updated README
• #767016 by jhahn: only attach behaviors once
• #361147 by Jose Reyero, mathieu, neurovation.kiwi, jhedstrom, miro_dietiker, dereine: add actual support for different textgroups
• #323917 by pvasili, andypost: trim user key on submission when saving to user data store
• #329472 noticed by hass, patch by mysalf: array_fill() and implode() warnings when no textgroup was selected for cleanup
• #264203 by neochief, dereine: disable submit buttons while submission happens to avoid users hitting them multiple times
• #616106 by alex_b, myself: #edit-target might not the ID of the target textarea, so add a specific class to it and use the cascade to look it up
• #593258 by lenart: increase zindex to make sure the bar appears always on top
• Quick fix for change in _locale_import_one_string_db()'s internal API (inspired by #748664)
• #559944 suggestion by murokoma: do not check off the default textgroup cleanup checkbox by default to avoid accidents
• #550516 by sinasquax and myself: IDs on form elements might not be the same if other forms exist on the page, so we should use other ways to look up the elements we need
• #550516 follow up fix for search clear button name mismatch
• #673092 idea by wouter99999, code by myself: non-submit buttons were not themeable and were not using the normal form API structures; they should
• #774794 by miro_dietiker, dereine, myself: add support for per-user setting to hide the l10n_client, so people can opt out from the performance hit when not in need of the functionality