Fix error, that multiple gravity behaviors are added to animator
Fix bug, that queued notifications would be animated out

The first condition always set the gravityAnimationCompletionBlock to
NULL, _after_ the next notification set it’s block.
Only initiate Animator, when needed.
Fixed notifications not being dismissed when `animated` is NO
have travis-ci upgrade `xctool` before building
Merge pull request #39 from vIiRuS/spamfix

Fix for #33
Merge pull request #43 from Ashton-W/issues/42-dismiss-animation

Fixed notifications not being dismissed when `animated` is NO
Merge pull request #46 from Ashton-W/issues/travis-fix

have travis-ci upgrade `xctool` before building
Fixed Toast view making the statusBar visible when user has it hidden. Fixes #44
Merge pull request #48 from cruffenach/Ashton-W/issues/44-hidden-status-bar

Fixed Toast view making the statusBar visible when user has it hidden. Fixes #44
rebase master and merge changes with develop