skip expiry test for memcache on travis

fixes #877
print travis ENV
travis memcache env check: try again
simplified travis env check for memcache(d)
set error_reporting for tests
made gridview plural rule compatible with ICU version < 4.8

issue #1072
added unit test to verify storing of null values

http://www.yiiframework.com/forum/index.php/topic/48359-inserting-nulls/page__view__findpost__p__226019
fixed unit tests for cubrid and postgresql

both do not support unsigned integers
refactored Component::off().
Fixes #1025: Implemented support for class-level events.
Typo [skip ci]
Merge pull request #1101 from lucianobaraglia/master

Typo [skip ci]
Added note about "Inconsistent types declared for an argument: U_ARGUMENT_TYPE_MISMATCH" ICU error to i18n docs
Added info about class-level event handlers to doc
fixed gridview message pattern
made intl messages more compatible with various ICU versions

issue #1072
Fixes #1106
Fixes #1104. Model generator table names auto complete.
Merge pull request #1109 from resurtm/fixes-1104-gii-table-autocomplete

Fixes #1104. Model generator table names auto complete.
fixed typo