Fix download protocol in OmniFocus.app Cask

Changed https to http because the former has stopped working
smartgithg: update to 6.0.4
Readme: update install instructions
Changed link name to 'Marked 2.app'.
Merge pull request #5444 from lgw4/marked

Changed link name to 'Marked 2.app'.
Upgrade consul to 0.3.1
Merge pull request #5446 from lalyos/consul

Upgrade consul to 0.3.1
Updated RStudio to v. 0.98.978
Merge pull request #5447 from mskblackbelt/rstudio

Updated RStudio to v. 0.98.978
Upgrade Hermes.app to v1.2.2
Merge pull request #5448 from jconley/hermes

Upgrade Hermes.app to v1.2.2
Update IntelliJ IDEA to 13.1.4

Additionally, reuse `version` stanza to facilitate future updates
Merge pull request #5449 from ndr-qef/intellij-idea

Update IntelliJ IDEA to 13.1.4
Update slack symlink

Similar to #1249

Seems that when Slack is unarchived it is named "Slack 0.44.2.app" instead of the "Slack.app" that is currently expected.

```
$ /usr/local/bin/brew cask install slack
==> Downloading http://slack.com/ssb/download-osx
Already downloaded: /Library/Caches/Homebrew/slack-latest
Error: It seems the symlink source is not there: '/opt/homebrew-cask/Caskroom/slack/latest/Slack.app'
```

```
$ /usr/local/bin/brew cask install test/slack.rb
==> Downloading http://slack.com/ssb/download-osx
Already downloaded: /Library/Caches/Homebrew/slack-latest
==> Symlinking App 'Slack 0.44.2.app' to '/Users/jmaclean/Applications/Slack 0.44.2.app'
slack installed to '/opt/homebrew-cask/Caskroom/slack/latest' (181 files, 8.4M)
```
Merge pull request #5451 from vitorgalvao/fix-5450

Update slack symlink
Update MPlayer OSX Extended to rev15
Merge pull request #5453 from vitorgalvao/fix-5452

Update MPlayer OSX Extended to rev15
Updated PDFpen to version 'latest'
Merge pull request #5457 from mskblackbelt/pdfpen

Update PDFPen to version 'latest'
Upgrade Macaw.app to v1.5