Prefer Ruby 2.0; require 1.9.3+
Improve img alt attribute for screen readers

Currently, the img_alt method in ActionView keeps underscores
in the alt attribute. Because underscores are pronounced in
Apple's VoiceOver Utility, this has serious implications for
accessibility. This patch makes underscored or hyphenated file
names (both common in projects) read more naturally in screen
readers by replacing them with spaces. See method documentation
for details.

Added documentation to image_alt method
added compress options for gzip

added test for compress options of gzip

update changelog
Merge pull request #7730 from beyond/gzip

added compress options for gzip
Update to latest Unicode data.

Release notes at: http://www.unicode.org/versions/Unicode6.2.0/
Remove method redefined warning

In `i18n` gem, the method definition of  `Hash#deep_merge!` is skipped
when it is already defined.

- warning: method redefined; discarding old deep_merge!
Merge pull request #8643 from tricknotes/remove-method-redefined-warning

Remove method redefined warning
Merge pull request #9238 from norman/unicode_62

Update to latest Unicode data.
Supress warning about method redifinition

In i18n gem, the following methods are defined.
- `Hash#except`
- `Hash#slice`

But if there are defined already, i18n skips these definitions.
So these definition by `active_support` are required before `require 'i18n'`.
Merge pull request #9240 from tricknotes/supress-warning

Supress warning about method redifinition
fix a typo on the engine guide
Merge pull request #9245 from vasconcelloslf/fix_guide_typo

fix a typo on the engine guide
fixing bit string test
Merge pull request #9221 from thenickcox/image_alt_attribute

Improve img alt attribute for screen readers