use # for comments and ; as delimiter for single line expressions

[knarz]

This PR should allow to write one-liners as outlined in #43 such as

push1 42; push1 13; sstore;

push1 42; push1 13; sstore

push1 42; push1 13; sstore
push1 42

[SamWilsn]

Hey! Thanks for your contribution to ETK. It's very much appreciated!

There are two doctests in the book that are failing (and unfortunately the CI isn't set up to run correctly on PRs.)

In doc/src/ch02-lang/README.md there's an old-style comment left over, and in doc/src/ch02-lang/ch02-labels.md there's a slightly different error.

You can run the book tests locally with the following, from the repository root:

mdbook test doc -L ./target/debug/deps

[knarz]

Looks like the error in doc/src/ch02-lang/ch02-labels.md is also present in master. Gonna see if I can figure that one out tomorrow

[SamWilsn]

Looks like the error in doc/src/ch02-lang/ch02-labels.md is also present in master.

mdbook test is pretty naive. You might need to cargo clean && cargo build after switching branches?

The other test passes now though :D

[knarz]

Rusty! The issue with the mdbook was that now the single line comment # and it has the value 0, since it is got stripped of its # because it got interpreted as being a comment for mdbook.

[lightclient]

Thanks a lot for your pull request. Very much appreciated :) Now that we can write one-liners, I think this makes etk a pretty good replacement for LLL tests in ethereum/tests.