Initial MSSQL related commit.
Merge branch 'master' of github.com:yiisoft/yii2 into mssql

Conflicts:
	yii/db/Connection.php
MSSQL driver classes moved to the proper location.
MSSQL table metadata parsint (initial version).
MSSQL Schema: methods order changed, initial data type infer.
Initial MSSQL tests.
Merge branch 'master' of github.com:yiisoft/yii2 into mssql
#20 proposed architecture for bootstrap
Merge branch 'master' into bootstrap

* master: (33 commits)
  Skipped ApcCacheTest expire
  MS Windows EOLs → UNIX EOLs.
  Build command path fix.
  refactored RBAC.
  Added usage example of Theme.
  Added default class for theme.
  Fixes issue #172: Implemented new usage of widgets.
  code style fix of YiiRequirementChecker.php Renamed yiirequirements.php to requirements.php
  "YiiRequirementChecker" console view has been reworked to display requirements by blocks and in brief for the successful ones.
  Changed framework in dir structure to yii
  requirements.php typo fix.
  "requirements.php" has been added to "bootstrap" application.
  Doc comments and error messages for "YiiRequirementChecker" have been adjusted.
  Doc comments for "YiiRequirementChecker" have been updated.
  PHP version fallback for "YiiRequirementChecker" has been added.
  "YiiRequirementChecker::check()" has been updated allowing to accept filename for the requirements. Yii core requirements file has been composed.
  Check helper methods have been added to "YiiRequirementChecker".
  Web view for "YiiRequirementChecker" has been created.
  "YiiRequirementChecker::render()" has been implemented, console view has been created.
  added newline to end of header and body blocks in View
  ...
made some changes, fix some pitfalls, remove PHP_EOL
partial response added, new code-style applied
code style fix
string helper fixed, mime-type reverted
Merge PR #275 branch 'partial-response-enh' of https://github.com/Ragazzo/yii2 into Ragazzo-partial-response-enh

* 'partial-response-enh' of https://github.com/Ragazzo/yii2:
  string helper fixed, mime-type reverted
  code style fix
  partial response added, new code-style applied
Fixes issue #251: changed the signature of t() to be the same as v1.1
Logger: getTag()/setTag() error fixed.
Merge branch 'master' of github.com:yiisoft/yii2
namespace cleanup.
Fixes #143. UrlValidator and EmailValidator IDN support.
UrlValidator and EmailValidator IDN support fixes.