adds support for manipulating UIDatePickers with LPDatePickerOperation

* calabash_cucumber/date_picker.rb
    * contains date picker related functions
    * adds picker_set_date_time(<DateTime>) function for interacting
      with LPDatePickerOperation

* step_definitions/calabash_steps.rb - added 3 predefined steps
    * Then I change the date picker time to "10:45"
    * Then I change the date picker date to "July 28 2009"
    * Then I change the date picker date to "July 28" at "15:23"
  to serve as examples of how to use the new operation

* et.al. made the changes necessary to add the new modules to the gem

KNOWN ISSUES: does not support pickers in count-down mode

NOTE:

* operations.rb removed an ancient commented out function
  change_slider_value_to that came from briar because:
    a. it was commented out
    b. it did not work very well
Merge pull request #195 from jmoody/0.9.x-datepicker-change-date-operation

adds support for manipulating UIDatePickers with LPDatePickerOperation
add support for Xamarin Studio projects that don't contain .iOS directories, e.g., TicTacToe sample
adds calls to calabash-ios-server/calabash/gitversioning scripts
before and after the xcodebuild call.  this is part of the server
versioning strategy.

provides the following additional information when server_version
is executed:

    "git branch" => "0.9.x-add-git-versioning-information",
    "git revision" => "cdce959",
Merge branch '0.9.x-add-git-versioning-information' into 0.9.x-riseup-branch