Working against dbml file instead of real database

[ceth-x86]

Description

Sometimes there is no way to connect to real database and in this case it will be fine to work agains DBML file (which was created by sqlmetal https://msdn.microsoft.com/ru-ru/library/bb386987(v=vs.110).aspx) instead of real database.

Is it possible ?

[Thorium]

Currently we don't have any kind of caching. But you can create a local database and change the connectionstring on the fly.

This is kind of duplicate of #361

[voroninp]

There is a nice post about this problem.

But it would be nice to have an option for enabling dumping dbml file, if it's not present.