docs: summary of some TODOs in the core

[ebuchman]

Follow up from #1376

Writing

• Improve the intro and obj-cap page. Maybe borrow some of the content from REVIEW: App Tutorial for Academy #1078 @gamarin2
• Remove go get from the install instructions ... explain the make commands
• Better document Bech32 and addresses (from app1)
• Update for new Amino and demo the cdc.PrintTypes functionality (app2)
• Mention ChainID sooner (before it appears in app3 needed for signing)
• Update list of ABCI servers and be able to link directly to it
• Notes about panics (eg. in InitChain, BeginBlock, ... KVStore, etc.)
• Need a section on the crypto! Probably in App2 after Amino
• Explain how to initialize a project

Apps

• Register Accounts on Codec
• Write tests
• Use SendKeeper for App3

Design Questions / Changes

• Do we still need abort in CheckTx ? (app2)
• Update AccountMapper constructor (app3)
• FeeKeeper suddenly needed for AnteHandler in app3 - can we do without it in the AnteHandler constructor somehow? Else need to say we'll explain later.
  • FeeKeeper also does mapper stuff (marshalling/storing). Should explain
• SetAddrPeerFilter -> SetPeerFilterAddr

More ?

[jackzampolin]

Closing this as outdated as some of this has been fixed. Also we are going to be doing a doc re--architecture pre-launch and will be opening more issues to track that work.