Fix typos

A couple of obvious typos here
Merge pull request #116 from rlerdorf/patch-1

Fix typos
Merge http://github.com/yiisoft/yii2
Merge pull request #117 from vyachin/master

fix SecurityHelper description
Check apc.enable_cli for ApcTestCase unit tests
Call static::dumpAsString in VarDumper::dump

This way we can extend VarDumper::dumpAsString
Merge pull request #120 from rinatio/119-apc-cache-unit-test

Check apc.enable_cli for ApcTestCase unit tests
Merge branch 'master' of git://github.com/yiisoft/yii2 into var-dumper-dump-call-static-dump-as-string
Merge pull request #121 from rinatio/var-dumper-dump-call-static-dump-as-string

Var dumper dump call static dump as string
Merge http://github.com/yiisoft/yii2
preg_match(): Unknown modifier '0'