Add partial support for 8-bit loads

We're big-endian.
when we have this in memory:

00 01 02 03

And we need the first byte, we load the first 16-bit word:

0x0001

The first byte is then in the upper part of the word, and requires
a right shift by 8.
So any load into an 8-bit typed container needs to shift stuff.

So far, stores from/to the stack are exempted, they always load/store
full 16-bit words.

And a few othe rminor things. Like string null terminators.
And escaped characters in character literals.

Can you believe it's spelled 'literal', with a single t?
Me neither.

tools/cc.ebnf

@@ -145,7 +145,7 @@ struct_field: type IDENTIFIER sized_array* ";"
 IDENTIFIER: /[_a-zA-Z]\w*/
 COMMENT: /\/\/.*/
 HEX_LITTERAL: /0x[a-fA-F0-9]+/
-CHARACTER: /'[^']'/
+CHARACTER: /'([^']|\\n|\\r|\\0|\\t)'/
 
 
 %import common.WS