Added count and pagination.

[darrenfang]

I use connection.Select(predicate).Count() to get the count of entities, after read your codes, I found it is simple to implement the count method.

[darrenfang]

Hi, I added the following method in ISqlBuilder interface

string BuildPagination(string tableName, string whereSql, string orderBySql, bool orderByAsc, int pageNo, int pageSize);

[henkmollema]

@darrenfang could you split the count and pagination implementation into two pull requests?

[darrenfang]

@henkmollema ok.