Add RTL level property and print flag

Again, the RTL property controls whether textboxes will be
right-aligned, and that kind of stuff. It can't be font-bound, since
Space Station supports Hebrew characters and we want to be able to
support, say, a Hebrew translation or Hebrew levels in the future
without having to make a dedicated (or duplicated) font for it.
Therefore it's a property of both the language pack as well as custom
levels - like custom levels already had a <font> tag, they now also
have an <rtl> tag that sets this property.

Right now, we'll have to hardcode it so the menu option for the Arabic
font sets the <rtl> property to 1, and all the other options set it to
0. But it's future-proof in that we can later decide to split the
option for Space Station into an LTR option and an RTL option (so both
"english/..." and "עברית" would select Space Station, but one sets the
RTL property to 0 and the other sets it to 1).

desktop_version/src/FontBidi.cpp

@@ -282,11 +282,16 @@ bool is_joiner(const uint32_t codepoint)
     return codepoint == 0x200C || codepoint == 0x200D;
 }
 
-bool bidi_should_transform(const char* text)
+bool bidi_should_transform(const bool rtl, const char* text)
 {
     /* Just as an optimization, only run the whole bidi machinery if the
      * language is actually an RTL one, _or_ if an RTL character is found. */
 
+    if (rtl)
+    {
+        return true;
+    }
+
     const char* text_ptr = text;
     uint32_t ch;
     while ((ch = UTF8_next(&text_ptr)))
@@ -313,7 +318,7 @@ bool bidi_should_transform(const char* text)
     return false;
 }
 
-const char* bidi_transform(const char* text)
+const char* bidi_transform(const bool rtl, const char* text)
 {
     uint32_t utf32_in[1024];
     int n_codepoints = 0;
@@ -345,7 +350,12 @@ const char* bidi_transform(const char* text)
     {
         return text;
     }
-    SBParagraphRef paragraph = SBAlgorithmCreateParagraph(algorithm, 0, INT32_MAX, SBLevelDefaultRTL);
+    SBParagraphRef paragraph = SBAlgorithmCreateParagraph(
+        algorithm,
+        0,
+        INT32_MAX,
+        rtl ? SBLevelDefaultRTL : SBLevelDefaultLTR
+    );
     SDL_assert(paragraph != NULL);
     SBUInteger paragraph_len = SBParagraphGetLength(paragraph);
     SBLineRef paragraph_line = SBParagraphCreateLine(paragraph, 0, paragraph_len);