Improve the generated password function(Genaration of stronger passwords)

Added a checkbox to the optionsDialog window which allows the user to choose either including or not Escape Characters(!@#$) to generated passwords. The above checkbox is set true by default on preferences. Also, added  some methods into AccountDialog.java in order to verify that the generated password:
1) contains  at least 1 lower case + 1 upper case + 1 number + 1 escape character, if the user has selected the checkbox to include Escape Characters
2)  contains at least 1 lower case + 1 upper case + 1 number, if the user has not selected the checkbox to include Escape Characters.
Also updated upm_el.properties fille.