Update classes/cache/storage/file.php

If subsection is defined, also delete subsection directory.
Added Content-Length to the Response
This now counts the string length of the response body and outputs
the Content-Length header accordingly.

Signed-off-by: Tom Schlick <tom@tomschlick.com>
switched to  multibyte length function (mb_strlen)

Signed-off-by: Tom Schlick <tom@tomschlick.com>
Checking if mb_strlen exists first

fall back to strlen
using MBSTRING
removed the Log class, is replaced by the Log package
have logger() write logs to the profiler console
replaced loading the Log class by loading the log package in logger()
have logger() validate the log level passed for monolog compatibility
fixed broken log level filtering
removed the Log class unit tests
Merge branch '1.5/develop' of https://github.com/fuel/core into 1.5/develop
rethrow exception in DBUtil::table_exists if no connection was made
Merge pull request #1261 from tomschlick/request-content-length

Added Content-Length to the Response
Merge pull request #1255 from bijsterz/patch-2

Update classes/cache/storage/file.php
Throw an exception if an non-existing file instance is requested. Closes #1248
reverted c0dad779c573bcb2560f2473ff4a534984185f9b, to many side effects
added finder file caching. closes #1260
added single and double quotes as valid-string options. closes #1251
added Mongo_Db::get_cursor()
added a new method to directly get the mongodb cursor from the mongodb class
this is useful for things like data processing so you dont have to load the
whole dataset into memory. also switched the Mongo_Db::get() method to use
this method when it needs to communicate with the db to keep everything DRY.