Adds spec for opening pipes in write mode via Kernel#open
Fix spec covering the encoding of Array#inspect with 1.9

Array#inspect uses the encoding of the string returned by Object#inspect
ran against the first entry of the array. Object#inspect will call
String#inspect, which does _not_ take into consideration the encoding of
the String object but will rather rely on the default external encoding.

Hence the spec must be rewritten to take into consideration the default
external encoding.
Check 29170 after exists returns false.
Merge branch 'master' of http://github.com/rubyspec/rubyspec into exist_fix
group_by returns hash without default_proc
Add specs for Kernel#instance_variable_set in frozen objects
Adjust spec definitions for Symbol#succ, Symbol#next
Make Mutex#sleep spec a bit less racy.

The sleep spec attempts to spin the spec thread until the Mutex
thread has both locked and slept by checking thread status ==
"sleep". However, part of the behavior of Mutex#lock is that if
it has to block it must go into "sleep" status. On most impls, it
is not possible to set thread status to "sleep" and attempt to
lock atomically, so there's always a gap between the two. This
makes the spec racy, since it might see "sleep" during the attempt
to lock, and as a result fail the subsequent check for
Mutex#locked? because the lock has not occurred.

This change introduces a local variable "locked" that will be set
to true once we know the locking has completed. The spec now
waits first for that locked variable to go true, and then proceeds
to check wait for the thread to sleep. This should at least avoid
the lack of atomicity in thread status + Mutex#lock from causing
this spec to fail sporadically.
Merge pull request #205 from kachick/adjust-spec-symbol-next

Adjust spec definitions for Symbol#succ, Symbol#next
Merge pull request #203 from kachick/add-specs-kernel-ivar_set

Add specs for Kernel#instance_variable_set when self is frozen
Merge pull request #194 from kostya/group_by

group_by returns hash without default_proc
Revert "Use IO.autoclose on 1.9+ for fdopen"

This reverts commit 8c03eb0daa997273882b27a27a4003c2097d68e1.
Revert "Explicitly close file objects on fdopen"

This reverts commit c02c78b3899fcf769084a88777c63de0fcebb48d.
Fixed File#open, #reopen properly.
Fixed spec description.
Fixed style of Enumerable#group_by specs.
Add specs for Array#keep_if, Array#select! on frozen objects
Add spec for Array#delete_if on frozen objects
Add spec for Array#reject! on frozen objects
Add a spec for String#split retaining the original string's encoding