Temporary Fix in limit() when expression.is_Add is True

Please refer https://groups.google.com/forum/?fromgroups=#!topic/sympy/61pRw1PINUA

Currently,

>>> from sympy import *
>>> x=Symbol('x')
>>> limit(1+(1+1/x)**x,x,oo)
2

Desired,

>>> from sympy import *
>>> x=Symbol('x')
>>> limit((1+1/x)**x,x,oo)
E
>>> limit(1+(1+1/x)**x,x,oo)
1 + E