Add support for highlighting search results in all windows.

Add support for restore the cursor position.

Add supports for the persistence of search history, ex command history, and cursor position history.

Do not add a buffer if the opened file already exists in moe.

Normal mode: Add ga command
Normal mode: Add a message when pressing Ctrl-C

Insert mode: Auto-complete words in the buffer of other windows.
Inert mode: Exit with Ctrl-C

Replace mode: Exit with Ctrl-C

Ex mode: Add build command
Ex mode: If the suggested path is a directory, add / to the end of the string
Ex mode: Exit with Ctrl-C

Configuration mode: Added changeable settings

Settings: Add Persist setting
Settings: Disable auto delete of parenthesis by default

Fix: Typos, grammar errors, and consistency issues in the help
Fix: Auto-complete suggestion window behavior in Insert mode
Fix: P command doesn't work in Normal mode
Fix: The suggestion window suddenly closes Ex mode

Some refactor