Create Pester tests for API Helper cmdlets

[mkellerman]

• Get-TwitterApplication_RateLimitStatus
• Get-TwitterFollowers_IDs
• Get-TwitterFriends_IDs
• Get-TwitterLists_list
• Get-TwitterLists_Subscriptions
• Get-TwitterSearch_Tweets
• Get-TwitterStatuses_HomeTimeline
• Get-TwitterStatuses_Lookup
• Get-TwitterStatuses_MentionsTimeline
• Get-TwitterStatuses_Retweeters_IDs
• Get-TwitterStatuses_RetweetsID
• Get-TwitterStatuses_RetweetsOfMe
• Get-TwitterStatuses_ShowID
• Get-TwitterStatuses_UserTimeline
• Get-TwitterUser_Lookup
• Send-TwitterStatuses_DestroyID
• Send-TwitterStatuses_RetweetID
• Send-TwitterStatuses_UnretweetID
• Send-TwitterStatuses_Update