Fixed crashes on callbacks from JS

Blocks not copied when saved in lists inside bridge. That leads to
crash on callback from JS because callback block doesn't exist at that
moment.
Merge branch 'master' of git://github.com/xzeror/WebViewJavascriptBridge into blockCopy

Conflicts:
	WebViewJavascriptBridge/WebViewJavascriptBridge.m
v2.1.2
Merge branch 'master' of https://github.com/marcuswestin/WebViewJavascriptBridge
add iphone5 splash screen; add @szeror and @kelp404 to list of contributors