Change vec<,,vl_embed>::m_vecdata refrences into address ()

Change vec<,,vl_embed>::m_vecdata refrences into address ()

As preparation to remove m_vecdata in the vl_embed vector this
changes references to it into calls to address ().

As I was here it also fixes ::contains to avoid repeated bounds
checking and the same issue in ::lower_bound which also suffers
from unnecessary copying around values.

	* vec.h (vec<T, A, vl_embed>::lower_bound): Adjust to
	take a const reference to the object, use address to
	access data.
	(vec<T, A, vl_embed>::contains): Use address to access data.
	(vec<T, A, vl_embed>::operator[]): Use address instead of
	m_vecdata to access data.
	(vec<T, A, vl_embed>::iterate): Likewise.
	(vec<T, A, vl_embed>::copy): Likewise.
	(vec<T, A, vl_embed>::quick_push): Likewise.
	(vec<T, A, vl_embed>::pop): Likewise.
	(vec<T, A, vl_embed>::quick_insert): Likewise.
	(vec<T, A, vl_embed>::ordered_remove): Likewise.
	(vec<T, A, vl_embed>::unordered_remove): Likewise.
	(vec<T, A, vl_embed>::block_remove): Likewise.
	(vec<T, A, vl_heap>::address): Likewise.