/*!
* @class AlignCols
*
* @implements EqualityComparableConcept
* @implements RandomAccessContainerConcept
*
* @headerfile <seqan/align.h>
*
* @brief Pseudo columns container for row-based Align class.
*
* @signature template <typename TAlign> class AlignCols<TAlign>;
*
* @tparam TAlign The Align type.
*
* @fn AlignCols#iter
*
* @headerfile <seqan/align.h>
*
* @brief Iterator to the item at the given position in the alignment columns.
*
* @signature TIterator iter(cols, pos[, tag]);
*
* @param[in] cols The AlignCols object to get the iterator for.
* @param[in] pos The position to get the iterator for.
* @param[in] tag The tag to pick the type of the iterator.
*
* @return TIterator The resulting iterator. If <tt>TTag</tt> is the type of
* <tt>tag</tt> and <tt>TAlignCols</tt> the type of
* <tt>cols</tt> then TIterator is of the type
* <tt>Iterator<TAlignCols, TTag>::Type</tt>.
*
* @section Remarks
*
* If <tt>pos</tt> is out of range then the iterator is invalid.
*
* @fn AlignCols#value
*
* @headerfile <seqan/align.h>
*
* @brief Returns AlignCols value at a position.
*
* @signature TColumn value(alignCols, pos);
*
* @return TColumn The column, as determined by Value metafunction.
*/