Add support for local blob storage

This commit resolves #1023 

Added support for writing attachments to local (or UNC) paths.

- I have updated the work done for #1015 to support the Local storage
option in the status page ![jabbr -
status](https://f.cloud.github.com/assets/234704/1294568/71368ece-3086-11e3-98c7-100746bb1489.png)

- Updated the Administration page to reflect the new configuration
values:
-- LocalBlobStoragePath: This is the local path where files will be
written to  (e.g: d:\files).
-- LocalBlobStorageUriPrefix: This is the URI Prefix for the files to be
served from (e.g: http://static.jabbr.net/files/)

Both values must be configured for IsValid() to return true on the
LocalBlobStorageHandler. Only one of the providers
(LocalBlobStorageHandler or AzureBlobStorageHandler) should be
configured at one time.

A separate site must be configured in IIS or another web server in order
to serve the static file uploads, offloading it from the JabbR server
and allowing for a much larger CDN story to follow without additional
enhancements to JabbR.

When directories get too large, administrators may change the
LocalBlobStoragePath and LocalBlobStorageUriPrefix configuration values
to change where files are written from without impacting already
uploaded files.
 
![jabbr - administration 1](https://f.cloud.github.com/assets/234704/1297384/f5220d1c-30e0-11e3-9e05-cae212b879be.png)

- Added several string resources in LanguageResources.resx to support
the  Administration page additions

Here is a screenshot of it in action:

![jabbr](https://f.cloud.github.com/assets/234704/1294572/8c768d9c-3086-11e3-8806-8c01f1b7ce43.png)