gradebook 6.x-2.0-beta2

Changes since gradebook-6.x.2.0-BETA1:

• #382254: Two file support bugs by MGN: Fixed two file support bugs reported by bdangelo and madflute.
• by MGN: database modification: changed {gradebookapi_files} primary key to ('fid', 'nid'),
  and make fid field NOT NULL (since its a primary key).
• by MGN: Modified gradebook_list_page to show table only when there are two or more gradebooks. For
  one gradebook, bypass the list page altogether and go to the only option. And when the user is not
  affiliated wtih any gradebooks, a helpful message is displayed.
• by MGN: Fixed gradebook list page so only relevent gradebooks are shown to the user
• by MGN: Fixed width of earned and note fields
• by MGN: Modified earned and possible fields in gradebookapi database tables to be of type float
  instead of int. This will make future grade conversions/scales easier to implement later
  and allows for fractional points now.
• by MGN: Implemented hook_block to provide a block that lists all the current assignments for a
  student or teacher that will be due in the future. The list is sorted by gradebook and
  then by due date. The assignment titles are given, along with the total possible points
  and the date due. The assignment title links to the assignment node.
• by MGN: To allow finer control over the date settings (hours and minutes), I implemented a date_popup
  element from the date api. I don't want to require dateapi for this module, so its an
  optional feature. On the gradebookapi admin screen there is a checkbox which will enable the
  use of date_popup on the assignment forms. Leave it unchecked if you don't want it.
• by MGN: Added a custom date format element to the gradebookapi admin form. This optionally sets the
  date format used in the assignment block and and on the gradebook page.
• #367150: Allow file attachments to gradebook by MGN: Added file attachments for gradebook entries for teachers and students.
  This necessitated a new table gradebookapi_files, so its important to run update.php when
  upgrading. Also, many changes to gradebookapi to load, remove and otherwise manage these
  files. Added general gradebook configuration to allow students, teachers or both to attach files.
• #367154: Gradebook page only displays 10 entries by MGN: Fixed pager support for gradebook pages with many assignments or edit forms
  with many grade entries. Added general gradebook configuration of the number of grades to display
  on a gradebook page.
• by MGN: Redesigned grade_assigment_page and grade_student_page to call the same gradebook_grade_form. Less code to manage and a more consistent, uniform css-styled UI.
• by MGN: Changed the {gradebookapi_grade} 'earned' field so it can be null. This allows for grades to be
  reset to null when the grade is edited, if desired. It was previously being reset to 0. This
  also required a couple of minor changes to the gradebookapi_calc_grades function because earned
  can be null even when $grade is not.
• by MGN: Updated README.txt to explain new features.