report lines changed from pasting text

reimplemented the paste function in the edit box class
added check for paste key sequence in key press event handler
replaced insert new line function with insert text function
return key calls new insert text function with single new line string
new paste function gets text from clipboard and calls insert text

insert text function handles detecting when current line needs to be
reported as changed, reporting any new lines are inserted from the text
being, and determining the modification status of the last line changed
from the inserted text
inserted