[ANN] RubyInstaller 2.0.0

[Justin Baker]

## Ruby 2.0.0-p645

### This is a Security Maintenance Relase

Ruby 2.0.0 has gone into the state of the security maintenance phase.
This means there will be no more releases in the 2.0.0 series unless any
critical regressions or security issues are found.

### Important information

Please note that the installers in this release are *not digitally signed*.

You can read more about this in post at RubyInstaller group:
https://groups.google.com/d/topic/rubyinstaller/NhAqcepQ-Xw/discussion

#### Choosing 32bits vs 64bits

Before you download a 64bits version (labeled x64), it is important you
understand that not all gems, libraries or tools have been tested for this
version.

Things are pretty close, however it is still our recommendation you
use a 32bit release.

If you have a 64bits version of Windows, you can still use 32bits, as there
is no performance issue around it.

#### Existing pre-compiled gems might not be Ruby 2.0 compatible

Ruby 2.0 and 2.1 introduced ABI breakage which means compiled C extensions from
releases in the 1.9.3 or 2.1.X series will not run against Ruby 2.0.

**DO NOT install Ruby 2.0 on top of existing Ruby 1.9.3 or 2.1.X**, or
try to use compiled
extensions with it.

You will be required to force compilation of those gems:

gem install <name> --platform=ruby

This **will require you have the extra dependencies installed** for that gem to
compile. Look at the gem documentation for the requirements.

Please check each gem documentation and recent releases.

#### Do not use other DevKit version than the one recommended

This version of Ruby has been compiled and optimized for mingw-w64 GCC 4.7.2.

Use of older version of DevKit package to compile gems might result in
compilation issues during gem installation or simply segfaults.

Look for the DevKit installers identified with the name 'DevKit-mingw64-32' and
'DevKit-mingw64-64' for 32 and 64 bits respectively.

To be clear:

* For 32bits Ruby 2.0.0: download and install `DevKit-mingw64-32-4.7.2`
* For 64bits Ruby 2.0.0: download and install `DevKit-mingw64-64-4.7.2`

#### Known Issues

There are some issues with Development Kit configuration process that fails
to detect x64 installations of Ruby. You will need to manually edit
`config.yml` for it to work. See the following issues for details:

- https://github.com/oneclick/rubyinstaller/issues/221
- https://github.com/oneclick/rubyinstaller/pull/237

### MD5:
9d4def981900b5c62c3964841ca3e8cc *ruby-2.0.0-p645-doc-chm.7z
1a59c016a3ea0714b06d7a5f6aa4157a *ruby-2.0.0-p645-i386-mingw32.7z
d57d539b90f5bbf26550a9d1a3c33c33 *ruby-2.0.0-p645-x64-mingw32.7z
99923a423cb165f1ae0b040f736094ae *rubyinstaller-2.0.0-p645-x64.exe
355bc34a71914c2e8b2a2710227431c3 *rubyinstaller-2.0.0-p645.exe

### SHA256:
e4796cc0492b29c6fc5e416c1d573f5ebdca2a0faf7c7fbaa30a9f72a7fe99b1
*ruby-2.0.0-p645-doc-chm.7z
b80146dffa97b654b54b5be3dac07f2140e3abada4707994bbd0455827977196
*ruby-2.0.0-p645-i386-mingw32.7z
cec14b304bd83e206426cf1d2edd31f37b41b90fdba69fe7b4c0b2d40a312ba3
*ruby-2.0.0-p645-x64-mingw32.7z
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*rubyinstaller-2.0.0-p645-x64.exe
9bfb1dfc6e24731570635ed39316a3f4541b12bf4b133605e51cfe577838cdc8
*rubyinstaller-2.0.0-p645.exe

### Official Announcement:
* https://www.ruby-lang.org/en/news/2015/04/13/ruby-2-0-0-p645-released/

### Enhancements:
* Upgraded Ruby 2.0.0 to patchlevel 645