Ensure nested parenthesis are handled into links

Make sure that parenthesis inside the link's url are correctly parsed
Redcarpet considered the first ")" occurrence as the link's end so we
first count the number of open "(" and decrement this number each
time we found a ")".

Close issue #237
Merge pull request #258 from vmg/nested-parenthesis-links

Ensure nested parenthesis are handled into links
correct `render_man.rb` filepath
Merge pull request #259 from suan/patch-1

correct `render_man.rb` filepath
Optional highlight support
`<mark>`!
Changelog entry for highlight
Merge pull request #263 from soffes/highlight

Optional highlight support
Move the last changelog entry to the top
Fix FTP uris identified as emails

Ensure FTP uris are correctly parsed and not considered as an email
address. This commit fixes #170.
Merge pull request #264 from vmg/ftp-uris

Fix FTP uris identified as emails
Remove the Sundown submodule from the repository

Since Sundown is deprecated we can remove it from the submodule list
and we won't pull code from it anymore so we can remove related rake
tasks. This way, the `tasks` folder is useless so let's gather tests
tasks and Rakefile.
Merge pull request #265 from vmg/remove-sundown

Remove the Sundown submodule from the repository
Add a changelog entry for previous commit
Remove comments related to Vim's syntax [ci skip]
Lock some dependencies to avoid failures on Travis

Nokogiri 1.6 doesn't support Ruby 1.8.7 anymore, we should lock it
to 1.5.9. Lock other development dependencies to prevent this kind
of issues in the future.
Merge pull request #269 from vmg/nokogiri-failure

Lock some dependencies to avoid failures on Travis
Make emphasis wrapped inside parenthesis parsed

Previously, when an emphasis was put inside parenthesis, the option
no_intra_emphasis return it as is. This commit fixes this issue. It
is a redundant issue in tutorials or in readme files.
Merge pull request #270 from vmg/wrapped-emphasis

Make emphasis wrapped inside parenthesis parsed
Merge remote-tracking branch 'upstream/master'

Conflicts:
	redcarpet.gemspec