fix: cursor position won't go negative when moving up and down

Previously the cursor position could have a negative horizontal value,
which would result in garbled output.

Signed-off-by: Ricky Ayoub <rayoub@redhat.com>
add find command to locate a specific term in the document

Find vocabulary can now be used to situation the cursor at the position
of the query, much like Vim.

Refind vocabulary is also added to quickly repeat the last find search
that was executed.

Finding will locate the next instance of the search term at the current
position + 1. it will loop around if the search hits the end of the
document.

Signed-off-by: Ricky Ayoub <rayoub@redhat.com>
adds save&quit, moving to start and end, and loading from argument

This patch allows for commands like ":wq" to work, as well moving to
start and end of the document with Vim-style "gg" and "G".

If a first argument is passed to the script, it will be loaded at the
start of editing.

Signed-off-by: Ricky Ayoub <rayoub@redhat.com>