Add function to drop individual table.  Refactor droptables to keep single codebase.
"MySQLDialect.CreateTableSuffix()" now panics if called with uninitialized values
Adds a SetUniqueTogether method on TableMap.

SetUniqueTogether adds uniqueness constraints across multiple columns
of a table. Much like setting a single column as unique, this
constraint is used *only* during table creation and not during
insert/update. SetUniqueTogether may be called multiple times, which
sets additional constraints.
Remove accidental "t.Error(err)" at the end of the SetUniqueTogether test
Merge branch 'mysqlDialectPanic' of https://github.com/LeGEC/gorp into LeGEC-mysqlDialectPanic
TestWithTimeSelect: add 1 second to w2 row to avoid timing issues with mysql
Merge branch 'unique-together' of https://github.com/Nitron/gorp into Nitron-unique-together
generalize trace logging mechanism
Add docs about GorpLogger interface
Return a sql.ErrNoRows when SelectOne does not return any row.

The SelectOne wants to return just one row, so it should also return an error
when no rows were returned. In this case, this function will return an
sql.ErrNoRows, as it's done in some functions of the database/sql package.
minor doc change on SelectOne() in readme
Update docs for SelectOne to reflect the code.
Postgres type of unlimited size is text. Using text over varshar is recommended by postgres community
gofmt
#108 - merge PR into develop
Complete implementation of interface for sqlite and mysql
Add support for go-sql-driver in test suite
Added Failing Test for Overridden Fields

Simply mapping any table with any overridden field causes the tests to fail, at least with the postgres dialect.  This commit adds a struct with an overridden field and maps it to cause the tests to fail.
Fixed Overridden Fields

With this commit, any embedded structs with fields that are overridden in the base struct will have their fields overridden in the dbmap, too, so that the column isn't used twice in database queries.
Updated Overridden Fields Logic

First, I added breaks in the loops to check for overridden fields when mapping a struct to a table.

Second, I modified the condition to the check to see if a field is considered 'overridden'.  Originally, it was only considered overridden if the column name was the same, but that meant that if you overrode the struct field but added a db tag to set the column name, the overridden field would still be added to the column map (using the field name).  This didn't make much sense.

This updates the conditional to check the field name instead of the column name for overriding purposes, which seems to make more sense.  It could possibly allow more database errors than the prior way of handling this, but I would consider those instances bugs in the underlying code, not in gorp.