vk and myspace are removed for now
added google plus sdk as pod
initial implementation of the google plus client added
implemented google plus client without using google iOS sdk
google iOS sdk removed
fixes of the google plus example for the new implementation
Merge branch 'google-plus'

Conflicts:
	SNTests/SNTests/AEViewController.m
added comment about choosing between openURL and custom WebView
added lin class method, which returns current client object. sso implementation added
unnecessary element removed from app plist
fb client code cleaning
li client code cleaning
generic oauth client code cleaning
twitter sso example added
fixed issue with oath authorisation stage. (incorrect encoding prevented from show correct authorisation page)
static client access methods renamed
two methods renamed. word 'get' was too ambiguous
unnecessary sources removed
documentation for generic sn and oauth clients added.
minor code reformatting