Merge pull request #5 from xhzengAIB/master

update codes
fix the images form cocoa pods nor working.
Update README.md
Update v0.1.5
Merge pull request #6 from xhzengAIB/master

update codes
add audio
Merge pull request #41 from Aevit/master

add audio (to do: change the length of the audio bubble according to the duration of the audio)
Roll back.
Fix multiple input type changes bug.

fix  https://github.com/xhzengAIB/MessageDisplayKit/issues/35
Change the file directory.
Add more controller class due with display message
Add more base controller class.
Change display controller super class.
Delete no use code.
Publish header to framework.
Fix the bug form input view layout frame.

fix https://github.com/xhzengAIB/MessageDisplayKit/issues/45
Update README.md
Update README.md
Update README.md
Update README.md