Created ActiveRecord::Tasks::SQLServerDatabaseTasks class

which addresses compatibility issues with Rails v4.1.8.

This is not yet a complete implementation of the ActiveRecord::Tasks
interface.

Adds test cases in test/cases/tasks/sqlserver_rake_test_sqlserver.rb

requires the new sqlserver_database_tasks from
lib/activerecord-sqlserver-adapter.rb

Updates to test/cases/(associations_test_sqlserver &
resolver_test_sqlserver) to address failing tests.

Added tags to .gitignore so ctags index files won't be checked in.

Fixed typo in RUNNING_UNIT_TESTS.md.
I'm not sure "tags" is appropriate to add. In general, this file has become more garbage. I'm OK with `ruby-` stuff for managers. If "tags" is something that you put into all of your projects ignore, perhaps take a look at this [global git ignore](http://robots.thoughtbot.com/global-gitignore) article. I put things like this in there...

```shell
$ cat ~/.gitignore 
.DS_Store
tmp/restart.txt
.powenv
.rake_tasks
activerecord/test/config.yml
misc_scripts/*
config.codekit
```