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
"yii\console\controllers\AssetController" has been updated:
 - assetManager has been converted into virtual property
 - bundle dependency load has been fixed
Unit test for "yii\console\controllers\AssetController" has been adjusted.
Method "yii\console\controllers\AssetController::loadBundleDependency()" has been improved allowing dection of the circular dependency.
E_NOTICE at "yii\console\controllers\AssetController::loadBundleDependency()" has been fixed.
"yii\console\controllers\AssetController::getAssetManager()" has been updated enforcing 'basePath' and 'baseUrl' config parameters.
Merge branch 'asset-command' with 'master'
Do comments at "yii\console\controllers\AssetController::saveTargets()" has been adjusted.
Fixes #145. Reusable cache dependencies.
Merge upstream/master into upstream/mssql.
Refinements to MSSQL driver classes.
MSSQL initial query builder.
MSSQL AR tests.
Better naming. Additional newline. Doctype tiny fix.