Adds OmniAuth::LDAP::Adaptor#bind

- Used to test ability to bind to LDAP server using current config
- Does not filter and verify by uid
Added Net::LDAP::Entry object to strategies test
Added respond_to? check to user mapping function

Net::LDAP::Entry returns empty array if key not
exists, so we should check for key with respond_to?
Using ruby-net-ldap master (0.4.0 - 8a182675f4)

- Using omniauth 1.1.3
- Using debugger gem for ruby 1.9.x
Use teambox fork of ruby-net-ldap

* Contains utf-8 fixes for BER strings
Adding explanation of branches
Merge pull request #1 from teambox/feature/add-simple-bind-method

Adds OmniAuth::LDAP::Adaptor#bind
Merge branch 'develop' into teambox