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

lib/PayPal/Api/ErrorDetails.php

@@ -4,45 +4,50 @@ namespace PayPal\Api;
 use PayPal\Common\PPModel;
 use PayPal\Rest\ApiContext;
 
-class ErrorDetails extends PPModel {
-	/**
-	 * Name of the field that caused the error.
-	 *
-	 * @param string $field
-	 */
-	public function setField($field) {
-		$this->field = $field;
-		return $this;
-	}
+class ErrorDetails extends PPModel
+{
+    /**
+     * Name of the field that caused the error.
+     *
+     * @param string $field
+     */
+    public function setField($field)
+    {
+        $this->field = $field;
+        return $this;
+    }
 
-	/**
-	 * Name of the field that caused the error.
-	 *
-	 * @return string
-	 */
-	public function getField() {
-		return $this->field;
-	}
+    /**
+     * Name of the field that caused the error.
+     *
+     * @return string
+     */
+    public function getField()
+    {
+        return $this->field;
+    }
 
 
-	/**
-	 * Reason for the error.
-	 *
-	 * @param string $issue
-	 */
-	public function setIssue($issue) {
-		$this->issue = $issue;
-		return $this;
-	}
+    /**
+     * Reason for the error.
+     *
+     * @param string $issue
+     */
+    public function setIssue($issue)
+    {
+        $this->issue = $issue;
+        return $this;
+    }
 
-	/**
-	 * Reason for the error.
-	 *
-	 * @return string
-	 */
-	public function getIssue() {
-		return $this->issue;
-	}
+    /**
+     * Reason for the error.
+     *
+     * @return string
+     */
+    public function getIssue()
+    {
+        return $this->issue;
+    }
 
 
 }