* Changed behavior of `f` to only add flag if there is none
* Changed behavior of `f+` to add flag in any case
* Moved listing subcommands from `f` to `fl`
* Moved listing subcommands from `f.` to `f.l`
* Added subcommand `f.l*` to list all local flags in all functions
* Listing flags at the current offset became `fl.`
* Moved `f=` to `fl=`
* Old `fl` (flag length) now became `fL`
* Removed original `fe` commands
* Old `f?` (check if flag exists) now became `fe`
* Removed `fV` commands
* Removed `fn` commands in favor of `fl` and `asm.flags.real=true`
* Removed `fS` commands (`fSo` and `fSn`)
* `fo` became `fortune` and moved from "flags" to "shell" category
* Removed oldshell handlers of the `z` commands
* Rename `sj`/`s*` and move them under `sH`. Remove `s=`
* Rename `s-*` to `sH-`
* Use `sd` for "seek delta", which moves relative to the current offset
* Enforce <cmd> <arg> syntax. So no more `s+16` but `s +16`. Command
`sHr` is for redo history, `sHu` for undo history. If one wants to move
relative to the current address, they need to do `sd +10`/`sd -10`.
* Remove `ss` commands in favour of `cmd.seek.silent`. This was anyway
used mainly for scripts, so no need to replicate all `s` commands
under `ss`.
Change a bit rz_core_seek API to avoid dupped entries in seek history.
