midgard-schema and database update

I ported some minor database routines from Midgard branch-1-9 to stable branch today. It doesn't mean I ported unstable features. On the contrary , I fixed quite important issues: #193,#214 and #78.

What does it mean exactly?

Datagard creates tables and adds some additional columns and indexes but only those mandatory like sitegroup or guid. midgard-schema is improved and make all database update more clever way:

• midgard_reflection_property is used to check if property should be indexed ( like parent property or link one )
• Indexes are created for commonly used metadata columns

When update is performed, midgard-schema checks every single table and column if anything should be done with it:

• Update is made as much faster as many unchanged columns you have in table ( comparing to shell's datagard )
• During developing, you may alter table and change columns' type "on the fly".