Until a 10, we don't have difference between DEC and HEX, may be print only DEC in these cases?

• moved lambda FormatSize to static function formatSize();
• extracted offset format code to static function formatOffset();
• always shows bytes in offset (for offset 4 showed Offset: 0 bytes and 4 bits)
• added render test for bit-fields

@sammccall review my code please

Extract formatting to lambda, for simplify code modification

Stores Offset, Size and Padding fields of HoverInfo in bits. When hover present bits converted to bytes, if possible.

In D151128#4365218, @sammccall wrote:

I do see the appeal of making this work for bitfields, but I think silently rounding offset/size/padding to whole bytes is pretty misleading.
For bitfields we'd really need to talk about layout at a bit level.
But we don't want to talk about regular fields in bits (I think?!)
And having a mixture seems like it's going to be pretty complicated both in implementation and for users, for a smallish feature.

I don't see a great sweet-spot design, maybe you/others have ideas (or can explain why the rounding behavior in this patch is reasonable.

Iterator checks may crash in current state. Also, pointeeType may return invalid type of iterator store (T* instead of T)