split main.js into multiple files

- main-drupal-functions.js: for drupal and non-ilscatcher funcs
- main-handlebars-functions.js: for handlebars helpers
- main-helper-functions.js: for helper functions?
- main-ilscatcher-functions.js: for ILS-related funcs
- main-vars.js: for all variable declarations
- existing main.js remains untouched, for now.

Signed-off-by: William Rockwood <wrockwood@tadl.org>