Use slots in the aiomysql proxy classes
Use slots in the aiomysql proxy classes

Add slots in the proxy cursor and connection classes in the aiomysql dialect

Change-Id: If72fccf0cc16557a7e3a0c9450733c8337bec15a

monetate/sqlalchemy,monetate/sqlalchemy,j5int/sqlalchemy,j5int/sqlalchemy,sqlalchemy/sqlalchemy,zzzeek/sqlalchemy