Removing Dependency from SDK Core Project

- Copied files required for Rest API SDK
- Removed PPApiContext and directly connected APIContext with PPConfigManager
- Removed duplicate data storage of configuration and credentials.
- Code Style Fixes
- Remove build.xml file as it is not required anymore
- Updated the samples
- Updated the documentations

release_notes.md

@@ -1,6 +1,11 @@
 PayPal PHP SDK release notes
 ============================
 
+v0.11.1
+----
+* Removed Dependency from SDK Core Project
+* Enabled Future Payments
+
 v0.11.0
 ----
 * Ability for PUT and PATCH requests
@@ -25,7 +30,7 @@ v0.7.0
 -----
 * Added support for Auth and Capture APIs
 * Types modified to match the API Spec
-* Updated SDK to use namespace supported core library 
+* Updated SDK to use namespace supported core library
 
 v0.6.0
 -----
@@ -34,4 +39,4 @@ v0.6.0
 
 v0.5.0
 -----
-* Initial Release
+* Initial Release