MySQL CreateTableGenerator workaround

Workaround for https://liquibase.jira.com/browse/CORE-1374.  This is probably not the best long term solution, but this will ensure the default dates/times that are actual dates and times (```1970-01-01 00:00:00```) will get passed as strings.  Currently, they are coming across as DatabaseFunction and thus go unquoted. Actual DatabaseFunctions, e.g. ```CURRENT_TIMESTAMP``` and ```NOW()``` will still get passed as functions. Same thing  with the ```ENUM``` datatype. 

It should be noted that this workaround  is to make the values that are generated in my generated changelog work. 

Also ```ENUM```s are not properly parsed in the generated changelog for MySQL.  Should be ```enum('Y','N')``` gets parsed as ```enum(2)```, which will fail on table creation.  But I see that is addressed in https://liquibase.jira.com/browse/CORE-1224.


Unrelated quick question:
Are there any plans to change the changelog generation order so that indexing happens before foreign key and unique constraints?  Currently I have to edit my 26k+ line generated file by hand to get the order right.