completed enemy revisions

reworked enemies for more complexity and elegancy of function.   Created
enemyinfo.lua for enemy reference to be recorded and referenced.  In
enemyinfo the function refEnemy(typeEn) is defined, it returns data
about enemies of a specified type.  Updated enemies.lua for
compatability, still need to complete revisions on bullets.lua for
compatability.
Changes made to bullets completed

need to edit ship.shots for compatablility
Merge pull request #11 from Izzette/master

compatability to bullets.lua from changes made to enemies.lua and enemiesinfo.lua