#7 Create forum DAL

[George Malyukov]

DAL (Data Access Layer) should be created for the "Forum" database.

Should contain classes & structures to use stored procedures. Logic for control data correctness ("null" values and so on) should NOT be added to DAL. These functions will be implemented in the wrappers level.

[George Malyukov]

Implemented User, Topic, Section and Category managers.

[George Malyukov]

Implemented AccessMask manager. Created structures for represent AccessMask and User tables information. Implemented methods to convert DataRow instance to AccessMask/User information structures.