fix #231 add rates with 3 digits behind comma like 0.007 or 0.015, make changes on database only
fix #231 my intention was to provide 10 digits credit instead of 7 digits, so now I changed them to decimal(13,3)
fix #231 also change input sizes
anything 'is_admin' should be changed to 'isadmin'
fix #227 admin users should be able to add sender ID for a user and approves it immediately, "created" is actually "last update", the time need to be adjusted
fix #227 update lang for sender id
fix #229 sender ID field removed from user/subuser add