Issue #610: /1.1/users/search count parameter malfunctioning

Count value has a maximum of 20.(https://dev.twitter.com/docs/api/1.1/get/users/search)
But paging seems to work on the assumption that count value is always 20.

When we test with count value 16, second page is supposed to start with 17th result but 21st one is coming.
No matter which number between 1 to 20 we set to count value, the first result of the second page is 21st one.

Logs below show that same id is coming for different requests.

================

count=15, page=2

[Request]
GET /1.1/users/search.json?q=snstest&count=15&page=2 HTTP/1.1

[Response]
[
{
"id": 115134804,
"created_at": "Wed Feb 17 18:32:45 +0000 2010",
"profile_sidebar_border_color": "C0DEED",
"entities": {
"description": {
"urls": []
}
},
...

================

count=16, page=2

[Request]
GET /1.1/users/search.json?q=snstest&count=16&page=2 HTTP/1.1

[Response]
[
{
"id": 115134804,
"created_at": "Wed Feb 17 18:32:45 +0000 2010",
"profile_sidebar_border_color": "C0DEED",
"entities": {
"description": {
"urls": []
}
},
...