improved evlib#evdebug#DebugMessage() performance & configurability
added vim scripts to ease library loading & initialisation
renamed files to accommodate new module names
added new 'test' directory with working tests

 * added new 'test/common.vim' with reusable test code;
  * dev tested;
 * added two "main" ("local" (i.e., not "remote")) tests:
  * test/vimrc_00_selftest-local.vim: tests 'common.vim' itself;
  * test/vimrc_01_init_source-local.vim: tests loading 'evlib' and
     making sure it works (basically);