smartgithg: update to 6.0.4
Readme: update install instructions
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
Add All The GIFs v1.0

Find GIFs, store your favourites, browse great sources. https://github.com/orta/GIFs
Merge pull request #5459 from vinkla/macaw

Upgrade Macaw.app to v1.5
Merge pull request #5460 from vinkla/all-the-gifs

Add All The GIFs v1.0
Merge pull request #5454 from eugenesan/syntevo

smartgithg: update to 6.0.4
Update Vagrant Manager to v1.5.5

  from version 1.5.2
Merge pull request #5462 from mariusbutuc/master

Update Vagrant Manager to v1.5.5
Update Intellij Idea Ultimate to 13.1.4
Make Vagrant Manager easier to update
Merge pull request #5463 from roddet/intellij-idea

Update Intellij Idea Ultimate to 13.1.4