Add tasks for all the new languages

Task/File-input-output/Phix/file-input-output-1.phix

@@ -0,0 +1,6 @@
+integer fn = open("input.txt","rb")
+string txt = get_text(fn)
+    close(fn)
+    fn = open("output.txt","wb")
+    puts(fn,txt)
+    close(fn)

Task/File-input-output/Phix/file-input-output-2.phix

@@ -0,0 +1,10 @@
+integer infn = open("input.txt","r"),
+        outfn = open("output.txt","w")
+object line
+    while 1 do
+        line = gets(infn)
+        if atom(line) then exit end if
+        puts(outfn,line)
+    end while
+    close(infn)
+    close(outfn)

Task/File-input-output/Phix/file-input-output-3.phix

@@ -0,0 +1,10 @@
+integer byte,
+        infd = open("input.txt","rb"),
+        outfd = open("output.txt","wb")
+    while 1 do
+        byte = getc(infd)
+        if byte=-1 then exit end if
+        puts(outfd,byte)
+    end while
+    close(infd)
+    close(outfd)