Don't preserve 'Demo' folder for cocoapod installs

Related update in cocoapods' repo: https://github.com/CocoaPods/Specs/pull/1691
Merge pull request #152 from yas375/patch-1

Don't preserve 'Demo' folder for cocoapod installs
Add HUD dismissal notifications and README documentation per issuecomment #13646255
Merge pull request #153 from danielamitay/master

Add HUD dismissal notifications.
Remove useless code.
Merge branch 'master' of github.com:samvermette/SVProgressHUD
Change references of SVProgressHUD to self or self.class.
guoxj:Careless person maybe forget，and then strange thing happens
Merge pull request #157 from guoxj/master

Add arc check
Fix #156.
Add UIAppearance support for custom images.

This allows customization of the default status images used by the
`+showSuccessWithStatus:` and `+showErrorWithStatus:` class methods:

    [[SVProgressHUD appearance] setHudSuccessImage:successImage];
    [[SVProgressHUD appearance] setHudErrorImage:errorImage];
Merge pull request #160 from jparise/image-appearance-support

Add UIAppearance support for custom images.
Clamp display duration to a maximum of 5 seconds.

If an exceptionally long display string were used, the HUD could
remain onscreen for quite a long time otherwise.
Merge pull request #168 from jparise/max-display-duration

Clamp display duration to a maximum of 5 seconds.