g-alleve.ads (Low Level Vector type definitions): Map each to the associated vector view instead of all to the unsigned char view.

2007-04-06  Olivier Hainque  <hainque@adacore.com>

	* g-alleve.ads (Low Level Vector type definitions): Map each to the
	associated vector view instead of all to the unsigned char view.

	* g-altcon.adb (Generic_Conversions): New internal generic package,
	offering facilities for all the Vector/View conversion routines
	implemented by this unit.
	(To_View/To_Vector - all versions): Reimplemented in a systematic
	manner, using the internal Generic_Conversions facilities.

From-SVN: r123570