Remove skydb (no longer in active development)

According to the [skydb github page](https://github.com/skydb/sky), the project is no longer in active development.
Merge pull request #175 from qjcg/patch-1

Remove skydb (no longer in active development)
Remove bitbucket.org/zombiezen/yaml package.

Package has been last updated in early 2013. The description says it implements a YAML 1.2 parser, but as we've learned at https://github.com/shurcooL/markdownfmt/issues/11#issuecomment-54249637, it has high level parsing functionality completely unimplemented and marked as TODO.
PHP Sessions Library
Fix new line
Add Distributed Systems section
Update README.md

Added heka, godropbox and vitess
Add "CSS Preprocessors" category & "gcss" package
Added Snapchat to third party packages
Added rrdaclient, wrapper for statdns.com API. DNS queries over HTTP
Merge pull request #181 from yosssi/patch-2

Add "CSS Preprocessors" category & "gcss" package
Merge pull request #182 from jamieomatthews/patch-1

Added Snapchat to third party packages
Merge pull request #180 from kpashka/master

Added heka, godropbox and vitess
Merge pull request #178 from fromYukki/master

PHP Serialize/Unserialize and session encode/decode functions
Merge pull request #177 from avelino/remove-inactive-unfinished-package

Remove bitbucket.org/zombiezen/yaml package.
Merge pull request #183 from Omie/rrdaclient

Added rrdaclient
Merge pull request #179 from otoolep/ds

Add Distributed Systems section
Add gotabulate

Generic Go Library for easy pretty-printing of tabular data.
Merge pull request #185 from bndr/patch-1

Add gotabulate
Merge pull request #1 from avelino/master

Changes form master