Update version number for release (#114)
* Add unit tests for Budget class
* Add unit tests for Percentage class
* Add unit tests for Percentage class (supplement to previous commit)
* Add unit tests for AddBudgetCommand
* Add unit tests for AddBudgetCommandParser
* Add unit tests for UniqueBudgetList
* Add unit tests for JsonAdaptedBudget
* Add unit tests for SwitchBudgetCommand
* Add unit tests for SwitchBudgetCommandParser
* Update UniqueBudgetList to automatically set newly added budget as primary
* Add Budget field to Expense
* Update AddExpense method in AddressBook to suit the new Expense with a Budget field
Specifically,
step 1: check primary budget - if null, add default and set primary, if yes - do nothing
step 2: check expense's budget - if null, add to primary budget, if yes - add to corresponding budget
step 3: add expense to expenses list
* Cosmetic changes: Remove extra whitespace
* Check null parameters in JsonAdaptedBudget constructor
* Update EditCommand following the changes to Expense class (new budgetName field)
* Add method to check which expenses are within current budget period
Other changes:
- add method to update the proportion used
- check for duplicate expense before adding
- change expired condition to include end date
- increase default budget limit
- cosmetic changes to make code more concise
* Change Expense's budgetName field type from String to Description
* Update tests following the addition of budgetName field to Expense class
* Fix checkstyle errors in Main and Test
* Update Percentage class such that percentage larger than 1 will be treated as 1 instead of throwing an exception
* Fix unit test failures due to addition of Category field to Expense
* Fix checkstyle errors in Main and Test
* Update DG: Budget feature (with class, sequence, activity diagrams)
* Fix checkstyle errors
* Cosmetic changes
* Fix minor GUI bug
* Update version number for release
