Problems updating from Piwik 0.1 to trunk #894

• warning when updating user_language
• installer does not prompt to re-use existing tables before database update
• mandatory updates don't consistently throw Piwik_Updater_UpdateException

Table inconsistencies between fresh install and upgrade path:

• the 0.2.33 update (utf8 conversion) misses tables created by plugins
• also in 0.2.33, TEXT fields became MEDIUMTEXT fields
• in 0.2.27, visit_goal_converted is inconsistent between Piwik.php and the update (VARCHAR vs TINYINT)
• the 0.2.12 update didn't drop the index_idaction INDEX on log_action table
• in 0.2.2 (there was no update), feedburnerName changed from NOT NULL to DEFAULT NULL on site table
• in 0.1.7 (there was no update), location_provider changed from NOT NULL to DEFAULT NULL on log_visit table

Re-open #522:

• tables created with login column still VARCHAR(20)

(In [1351]) fixes #894, refs #666 - fix problems and inconsistencies between fresh install and upgrade path

Only the utf8 side-effects of converting of TEXT columns to MEDIUMTEXT columns was unchanged.

(In [1352]) refs #894 - a little refactoring

(In [1354]) refs #894 - fix broken Updater.test.php

(In [1355]) refs #894 - generate friendly error message if configuration file exists but points to an empty database

(In [1356]) refs #894 - update comments

(In [1365]) refs #894 - updates for third party plugins