Display a table description in xml output the same way as 'describe table;'
command does it.
For example
for create table t1(a int, key(a));
...
<table_description>
<field_description>
<Field>a</Filed>
<Type>int(11)</Type>
<Null>YES</Null>
<Key>MUL</Key>
<Default>NULL</Default>
<Extra></Extra>
</field_description>
</table_description>
or
<table_description>
<field_description Field="a" Type="int(11)" Null="YES"...>
</field_description>
