Fixed parsing of __attribute__ just after struct keyword
Prevent structs in compound assignment
Better error message on assignment to non-lvalues

Array-types given higher preference (than dereference), otherwise we end
up with (after fold):

int x[10];

x = (int[10])2;

And we get an error about the cast, not the lvalue.
Fix default stack alignment
Fixed mixed code/decl scoping bug

Decls were getting hoisted, along with their assignments, e.g.
	int i;
	i = 2;
	int j = i;
would become:
	int i;
	int j = i; // uninit
	i = 2;
Merge branch 'master' into feature/bitfields
Fixed bitfield parsing with multiple decls

int a : 5, b : 2;
was parsed as int a : (5, b) :
                syntax error ^
0 can't be truncated in bitfield assignment
Added bitfield bit test
bf_lib not required - pretty confident on bitfield reads
Sign extend signed bitfields when reading
Better overflow checks on constant conversion