ESLifier-Merger ALPHA v0.0.1

Stripped a bunch of stuff from the original ESLifier as a base.
Added a "Starting Record Number" column so that users can manipulate the starting record number to renumber the records in a plugin.
Barely tested.
Removes the ESL flag from .esp/.esm files that it renumbers.
Ignores plugins that end in '.esl' as I'm lazy and don't want to rename the plugin name in all files.
Doesn't actually do any merging despite its name. Just called it that for when I may eventually convert it into a merging tool.