Increase strictness of base types

[lightclient]

Fixes #303.

• There is an inconsistency with the base types where some types with a numeric post-fix value accept only that quantity and other accept up to that quantity. This PR makes it so all types accept only that quantity (e.g. Bytes32 requires exactly 32 bytes), with the exception of integers. They will continue to accept values up to their quantity (e.g. 0x1 will match uint256).
• There is an error where Bytes65 was copied from Bytes512 and the bound was not updated. This has been resolved.
• There is an error with uint256 where 0x matched validly. It's been updated to follow the same pattern matching as other uint sizes, requiring no leading zeros.
• Some byte values actually have caps. I've added BytesMax32 for use with storage keys. They don't quite fall within the domain of uint256 (especially with the above fix) and they don't always serialize to 32 full bytes. This is the main issue in eth_getStorageAt spec ambiguity #303.
• Generally improved the readability of the definitions a bit.

[fjl]

Can this be merged?

[lightclient]

Yep should be good to go. I will merge it.