added writing capacilities to files and made the appropriate changes to the filedemo.c file

examples/file/filedemo.c

@@ -12,9 +12,12 @@ int main() {
     char* string = fileToString(f);
     printf("\"%s\"\n", string);
 
-    // TODO -> writing, clearing
+    printf("writing is quite simple, just call the 'fileWrite(file_t*, char*)' or 'fileWriteln(file_t*, char*)' function, where the second argument is the string you want to write into a file\nthe 'fileWriteln()' function writes the specified string AND a '\\n' after it, whereas the 'fileWrite()' function does not append the '\\n'\n");
+	fileWrite(f, "'this will not end with a \"\\n\"' ");
+	fileWriteln(f, "this line was appended");
+	filePrint(f);
 
-    printf("if you are finished working with the file BEFORE the immediate end of the program, run 'fileCleanup(file_t*)', otherwise it is not strictly necessary\n");
+    printf("if you are finished working with the file BEFORE the immediate end of the program, run 'fileCleanup(file_t*)', otherwise it is not strictly necessary\nit will, though, append a '\\n' at the end of the file if you have not done so, making writing into files more consistent, so for this reason, I recommend you use it with every file_t*\n");
     fileCleanup(f);
 
     return 0;