Terminator

Terminator - Terminal with enhancements

Terminator allows you to have multiple Windows,  split -windows etc. on a single terminal. You could run a build on window, and perform editing in other window. It is almost similar to Tmux, but not useful when using ssh.

Split window vertically

 ctrl+shift+e  

Split window horizontally

 ctrl+shift+o

Clear the contents of a window

 ctrl+shift+g

Navigate between tabs internally in a window

 alt+'up/down/left/right keys'  

Adjust size of a split window

 Hold 'ctrl+shift' then 'up/down or left/right keys'