Added exponential policy - 10% speed improvement
returns a valid pool of minimum size if exponential  is too big
Removed isOOM
Allow configuration of the signals used for GC

On Posix systems druntime's GC uses SIGUSR1 and SIGUSR2 to implement
suspension of threads for its garbage collector. When integrating D into
existing programs written in other languages such as C or C++,
SIGUSR1/SIGUSR2 may already have an existing meaning. This allows those
programs to use currently unused signals for D's GC, most likely some of
the POSIX real time signals where availble.

This is acheived by calling thread_setGCSignals prior to thread_init, at
most once. If it is not called the runtime will continue to use SIGUSR1
and SIGUSR2. The functionality leaves the choice of signals up to the
caller, it does not assume any particular real time signal or that real
time signals are available.
Fix identation
typedef support for hashOf
13377 - include core/sys/posix/syslog.d
Fix property enforcement in `core.time`.
Merge pull request #946 from denis-sh/fix-property-enforcement-in-`core.time`

Fix property enforcement in `core.time`.
Issue 13414 - Static destructors not called correctly with dynamic loading

Patch provided by Niklas Wallén in private correspondence.
Merge pull request #947 from klickverbot/run-tls-dtors

Issue 13414 - Static destructors not called correctly with dynamic loading
regression test for issue 13414
include syslog in windows builds
Merge pull request #948 from MartinNowak/test13414

regression test for issue 13414
Merge pull request #945 from klamonte/master

13377 - include core/sys/posix/syslog.d
Add missing import files in core/sys/osx/mach
Merge pull request #938 from sinkuu/missing_import

Issue 13377 - core/sys/posix/syslog.d is in druntime/src but not in druntime/src/import
Merge pull request #932 from IgorStepanov/newaa-hashof-fixes

[new AA] core.internal.hash fixes
localize some imports
peace deprecation warnings about shared read-modify-write ops