Add remixd tutorial

Fix solidity state

Improve mapping decoder

misc: Add link to example Dapp Front End. Add Geth block check command. Fix typo.

initial support for mapping types

- add we3.debug.preimage
- move mapping resolver from soliditystate to storageViewer

version change

eventManager as lib in index.js

Fix treeView style

Fix TreeView

Fix src map for abstract contract

fix caret placement for struct data