add morphisms

- unicode
- value delimited seq
- zigzag encoding (still lacking any way to get to signed integer yet'..)

morphisms/unicode.morphism-base

@@ -0,0 +1,93 @@
+```
+```
+
+morph_string_as_ascii_to_utf8 ()
+     <Seq ~ <ValueTerminated '\0'>  Char~Ascii~x86.UInt8>
+-->  <Seq Char~Unicode>
+    ~ UTF-8
+    ~ <Seq~<ValueTerminated 0> x86.UInt8>
+```
+    while( *src ) { *dst++ = *src++; }
+    *dst = 0;
+    return 0;
+```
+
+morph_string_as_utf8_to_ascii ()
+    <Seq Char~Unicode>
+    ~ UTF-8
+    ~ <Seq~<ValueTerminated 0> x86.UInt8>
+--> <Seq ~ <ValueTerminated '\0'>  Char~Ascii~x86.UInt8>
+```
+    while( *src ) {
+        if( *src < 128 ) {
+            *dst++ = *src++;
+        } else {
+            fprintf(stderr, "(morph UTF-8 to Ascii) ignore multi-byte character\n");
+            while( *++src >= 128 );
+        }
+    }
+    *dst = 0;
+    return 0;
+```
+
+morph_string_as_ascii_to_utf32 ()
+     <Seq ~ <ValueTerminated '\0'>  Char~Ascii~x86.UInt8>
+-->  <Seq Char~Unicode>
+    ~ UTF-32LE
+    ~ <Seq~<ValueTerminated 0> x86.UInt32>
+```
+    while( *src ) { *dst++ = *src++; }
+    *dst = 0;
+    return 0;
+```
+
+morph_string_as_utf8_to_utf32 ()
+
+      <Seq Char~Unicode>
+    ~ UTF-8
+    ~ <Seq~<ValueTerminated 0> x86.UInt8>
+
+-->   <Seq Char~Unicode>
+    ~ UTF-32LE
+    ~ <Seq~<ValueTerminated 0> x86.UInt32>
+
+```
+    bool has_multibyte = false;
+    uint32_t val = 0;
+    while( *src ) {
+        uint8_t tag = (*src >> 6)&0b11;
+        switch( tag ) {
+            // single byte
+            case 0b00:
+            case 0b01:
+                if( has_multibyte ) {
+                    *dst++ = val;
+                    has_multibyte = false;
+                }
+                *dst++ = *src++;
+                break;
+
+            // start multibyte
+            case 0b11:
+                if( has_multibyte ) {
+                    *dst++ = val;
+                }
+                has_multibyte = true;
+                val = (*src++) & 0b111111;
+                break;
+
+            // continue multibyte
+            case 0b10:
+                val <<= 6;
+                val |= (*src++) & 0b111111;
+                break;
+        }
+    }
+
+    if( has_multibyte )
+        *dst++ = val;
+
+    *dst++ = 0;
+
+    return 0;
+```