[phobos] phobos commit, revision 2018

[dsource.org]

phobos commit, revision 2018


user: rsinfu

msg:
std.typecons: Several improvements to Tuple.

- Tuple members are now accessible with the syntax a[0], a[1] etc.
- Eliminated an internal union (see bug 4421 and 4846). Re-implemented named members with alias.
- Worked around bug 4424. Got opAssign back.
- Made Tuple.slice!(from, to) to preserve field names if any.
- Added isTuple!(T) template.
- Removed the 'default constructor' that is never called.
- Changed Tuple.toString() to use formattedWrite() instead of the `static if (is(to!string...))` thingy.

http://www.dsource.org/projects/phobos/changeset/2018