Moved result construction more towards connector.
Fixed a few issues, added dynamic test (which does not work yet)
Can now yield a handle to a prepared statement
Added missing file
Can now bind integral parameters and execute prepared queries
Can almost bind results (interface OK, implementation required)
de-templatified result
uccessfully running the first prepared select statement including result evaluation
Successfully retrieved text results from a prepared statement
Added support for boolean results from a prepared query
Test with boolean and text parameters in prepared query compiles and runs
Adjusted tests for prepared select statements

Most noteably, prepare is not const anymore
Added support for prepared insert, update and delete
Merge branch 'feature/prepared_statements' into develop
Adjusted to recent changes in sqlpp11
Added first specialization for mysql's interpretation of SQL

concatenation of strings uses the CONCAT method instead of the ||
operator.
Removed obsolete flags
Added interpreter for insert with default values
Updated tests to recent changes in sqlpp11
Merge branch 'feature/vendor_specific_interpreter' into develop