Fix compile errors with Xcode 4.6.

The compiler fails to understand the typeof (self) syntax:

FPPopover/FPPopoverController.m:124:17: warning: type specifier missing,
defaults to 'int' [-Wimplicit-int]
        __block typeof (self) bself = self;
        ~~~~~~~ ^
FPPopover/FPPopoverController.m:124:25:
error: a parameter list without types is only allowed in a function definition
        __block typeof (self) bself = self;
                        ^
FPPopover/FPPopoverController.m:124:30:
error: expected ';' at end of declaration
        __block typeof (self) bself = self;

I fixed this by following the advice found at
http://stackoverflow.com/a/10921206/1147607