Merge pull request #552 from mcnewton/v3.0.x

allocate-update should be allocate_update for dhcp_sqlippool
Remove redundant escaping from sqlcounter
Escape %s in sqlite counter queries
Added rlm_unpack

Which makes it easier to unpack binary data
Note rlm_unpack
%% is a LITERAL, not a PERCENT expansion

PERCENT expansions are escaped.  LITERALs are not.
basic config for dhcp IP allocation using sqlite