use for loop instead of while in SEQUENCE 

This avoids side effects:

   my @abc = ^10; my @ = @abc ... 4; say @abc;

See IRC log for this day.
using binding for better performance

There were concerns about loss of performance with for loop instead of while/shift.  A binding instead of an affectation might help.
Make flipflop smartmatch against $_ instead of calling .Bool.
Add X::Syntax::Regex::SolitaryQuantifier
Add typed exception X::Syntax::Term::MissingInitializer
used for term definitions without initialization assignment (cmp RT #116607)
Liberalize attribute-having.

Make it so that custom declarators are allowed to have attributes to,
and use the default Attribute class as a fallback.
fix usage of Labels in REPL, discovered by psch++
Prevents double deprecation warning for spurt()
Temporarily remove deprecation removal
Temporarily remove deprecation removal
Undeprecate recently deprecated IO ops

Please revert this commit after release of 2014.10
fix a few wrongs with WINNER
Remove *.exists

It has been deprecated for > 1 year
Remove *.delete

It has been deprecated for > 1 year
Mention removal of .exists|.delete
Remove ucfirst, it has been deprecated > 1 year
Remove KeySet/KeyBag, deprecated > 1 year ago
Speed up Str.trans

It does this by removing matchers that have no chance
of matching again.

JSON::Tiny::to_string uses

$d.trans(['"',  '\\',   "\b", "\f", "\n", "\r", "\t"]
              => ['\"', '\\\\', '\b', '\f', '\n', '\r', '\t'])

With $d = "\n" x 10000, this patch reduces the run time from 13.5s
to 4.9s.
Str.trans: Fix regex context buglet

Previously, Str.trans used substr to extract a substring and then
match a regex against that substring. This messes up all kinds of
zero-width assertions (anchors, word boundaries, look-behinds).

Instead, use the Str.match(Regex, :continue($pos)) to tell the
regex engine where to start
Avoid repeated concatenation (O(n^2)) in Str.trans