Added an ability to provide Curl Options in Configuration

- Removed http.Retry, and http.ConnectionTimeout from configuration
- Added ability to provide Constant and its value in Configuration File

sample/sdk_config.ini

@@ -8,8 +8,10 @@ acct1.ClientSecret = EGnHDxD_qRPdaLdZz8iCr8N7_MzF-YHPTkjs6NKYQvQSBngp4PTTVWkPZRb
 
 ;Connection Information
 [Http]
-http.ConnectionTimeOut = 30
-http.Retry = 1
+; Add Curl Constants to be configured
+; The settings provided in configurations would override defaults
+; if provided in configurations
+http.CURLOPT_CONNECTTIMEOUT = 30
 
 ; Adding HTTP Headers to each request sent to PayPal APIs
 ;http.headers.PayPal-Partner-Attribution-Id = 123123123