update about 32 ops for gb_esil
Rename l to T, add cfg.user and 'TT' chat prompt

* Add cfg.user variable
* Implement TT chat prompt
* Invoked from 'VT'
* Rename 'l' to 'T' command (log -> textlog)
* Add r_sys_whoami () -> set default username
* Add $$ trap instruction in ESIL
* Implement POP and STACK esil commands
Now TT in sandbox mode and fix segfault in free
Fix r2.js webui with 'l'->'T'
Add TT in remote http console (r2 -C host:port)
Initial implementation for the remote visual mode
Initial background thread for the webserver (=h& and =H&)
add "++", "++=", "--" and "--=" to the esil-vm

(cherry picked from commit 3e6d7d73b7374991527b941ce1004995181a0669)