Added failure case signin feature specs for #234
Added failure case signin feature specs for #234

- spec/features/admin_spec.rb - Added descriptive comments explaining
  the conditions for success for each feature spec in the file.
  Also, each spec now contains the results of logging into both
  the main site as a user as well as the admin section as an admin.

  Also, the following scenarios were added:

  * User signin without admin credentials
  * Admin signin without any credentials
  * Admin signin with incorrect credentials

EBWiki/EBWiki,BOWiki/BOW,BOWiki/BOW,EBWiki/EBWiki,EBWiki/EBWiki,EBWiki/EBWiki,BOWiki/BOW