#419 - Fixed Illegal characters in path

Regex for getting the markdown link for AssociatedImages was also
pulling in the optional title. Since the optional title includes a "
character it was causing Path.IsPathRooted to fail. Updated the link
word boundary to exclude the optional title if present.
#419 - Added unit test for optional title fix

Added a unit test that includes an image with an optional title defined
as well as an image without.
Added support for a user created dictionary.
only one thread can use the settings file at once

#435 - FileSystemStorageSettingsStore can only have a single thread
reading and/or writing to the settings file.
using lock to sync threads using the settings file
Merge pull request #436 from kkostov/IOExceptionWhenUpdatingJumpList

only one thread can use the settings file at once
Adding french spell check
Merge pull request #437 from laedit/master

Adding french spell check
Merge pull request #428 from myquay/master

#419 - Fixed Illegal characters in path
Merge pull request #431 from mizipzor/issue387

Added support for a user created dictionary.