Add import functions to using!

Author: felek

main.fels

@@ -1,3 +1,3 @@
 using "fels.io.scanner"
 
-scanner.readLine()
+println(a())

prog.fels

@@ -1,3 +1,3 @@
-using sfm
+using "fels.lang.sfm"
 
 func a() = 2

src/main/java/net/felsstudio/fels/parser/ast/UsingStatement.java

@@ -7,6 +7,8 @@
 import main.java.net.felsstudio.fels.lib.Value;
 
 import java.lang.reflect.Method;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.Arrays;
 
 public final class UsingStatement extends InterruptableNode implements Statement {
@@ -26,6 +28,11 @@ public void execute() {
         final Value value = expression.eval();
         final String[] parts = value.asString().split("\\.");
 
+        if(Files.exists(Paths.get(value.asString()))) {
+            new ImportStatement(expression).execute();
+            return;
+        }
+
         String page = parts[1];
         String name = parts[2];