Several improvements (#9)

* fix icon filename

* update pp2d to fix preview problem

* several improvements:
- rely on a single header for simple/common headers
- cleaned up main by putting the interface drawing function in its own file
- load previews from .zip themes (may cause some loading times when launching
- only need 1 shuffle image thanks to pp2d's blending abilities

* not needed anymore

* fix preview color and position

* forgot

* add proper icon loading
thanks steveice10 for bannertool which this was pretty much taken from

* only add proper themes to the list

* add slightly more space between the icon and the name

* not monospace, the little movement every blink is annoying

* fix typo

include/common.h

@@ -0,0 +1,47 @@
+/*
+*   This file is part of Anemone3DS
+*   Copyright (C) 2016-2017 Alex Taber ("astronautlevel"), Dawid Eckert ("daedreth")
+*
+*   This program is free software: you can redistribute it and/or modify
+*   it under the terms of the GNU General Public License as published by
+*   the Free Software Foundation, either version 3 of the License, or
+*   (at your option) any later version.
+*
+*   This program is distributed in the hope that it will be useful,
+*   but WITHOUT ANY WARRANTY; without even the implied warranty of
+*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*   GNU General Public License for more details.
+*
+*   You should have received a copy of the GNU General Public License
+*   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+*   Additional Terms 7.b and 7.c of GPLv3 apply to this file:
+*       * Requiring preservation of specified reasonable legal notices or
+*         author attributions in that material or in the Appropriate Legal
+*         Notices displayed by works containing it.
+*       * Prohibiting misrepresentation of the origin of that material,
+*         or requiring that modified versions of such material be marked in
+*         reasonable ways as different from the original version.
+*/
+
+#ifndef COMMON_H
+#define COMMON_H
+
+#include <3ds.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define THEMES_PATH "/Themes/"
+
+static const int THEMES_PER_SCREEN = 4;
+
+enum TextureID {
+    TEXTURE_FONT_RESERVED = 0, //used by pp2d for the font
+    TEXTURE_ARROW,
+    TEXTURE_SHUFFLE,
+    MAX_TEXTURE,
+};
+
+#endif