Check sections in "instantiate"

For more load-time syntax checking.
Add note on status-server behaviour
Add redundancy for XLATs.

Via the "instantiate" section

	redundant my_sql {
		sql1
		sql2
		sql3
	}

And now "%{my_sql:...}" will work
Fail if we can't find an xlat by this name
Failed to register redundant xlat is a warning, not an error
Remove redundant connection pool indirection in rlm_sql
Rename LDAP connection functions to be consistent with sql and cache
Use C99 field labels when initialising driver structs

Means it's possible to add new callback functions in the module structs without having to go through and add NULL field initialisers to every module
Convert redundant checks to load time instead of run-time
Document redundant xlats
Document retry_delay
Fix typo
A better name
Minor formatting fixups
Allow for selective disabling of TLSv1.1 and TLSv1.2
Make tlsv1.2 and tlsv1.2 conditional on having them
dlclose driver handles on mod_detach (rlm_sql and rlm_cache)
More reformatting
lldb doesn't like this
Explicitly free children of rlm_sql and rlm_cache instances, before calling dlclose on the driver

Prevents SEGV when talloc tries to call destructors that have already been unloaded