Add tests for any_of combining scopes
FIX prepared statements messing up

When using arel level OR'ing, prepared statement and concataned
untouched. This is a problem because wildcards will use the same number
($1, $2, etc) in each statement, leading to a mismatch between expected
and provided statements.

Fixed by parsing strings and remapping wildcards.

Close #15

Conflicts:
	lib/activerecord_any_of/alternative_builder.rb