Add routines for finding AST nodes

WIP: Import fix for vscode integration

remove everything but link to new location of docs

Default abi if compiled with yul

Version bump

Set language for solidity compiler

fixing #2029 static Analysis Location Issue

Functions from remix-lib:
- sourceLocationFromAstNode
- nodesAtPosition
- getLinebreakPositions
- findNodeAtSourceLocation

Add walkFull that traverses more of the AST nodes. This is non-legacy
only.

remix-solidity: add compiler.setEvmVersion()

Small spelling typos

remove `console.error`

Location is a object instead of string(.src)

Docs update

Docs new layout

update for new layout

update for new layout

Add a way to pass the `evmVersion` parameter
to `solc` by:

1. Simplify the `Compiler.compileJSON()` interface from
`compileJSON(source, optimize)` to `compileJSON(source)`

Whether optimization is enabled is then always determined by
the `Compiler.optimize` object field which simplifies data flow.

2. Add a `Compiler.evmVersion` field and a setter and
make `compileJSON()` honor that.

Specifying `evmVersion` is useful when targetting an older
private chain with the latest `solc` or when using
an EVM-compatible chain that's slightly behind Ethereum
main-net in terms of features.

The unused `userAgent` variable in `onInternalCompilerLoaded` was
only removed to fix `npm run test` for `remix-solidity`'.

publish lerna

Various Fix on Debugger

add more methods to remix-sim; fix accounts