fix(lints): multiple linter rules #149

[Aadeesh11]

Fixes #149

Describe the changes you have made in this PR -
Enabled linter:

1. non_constant_identifier_names
2. unnecessary_parenthesis
3. avoid_redundant_argument_values

(in order of changes required for them, high to low)
Note: Please check Allow edits from maintainers. if you would like us to assist in the PR.

[coveralls]

Pull Request Test Coverage Report for Build 1541146921

• 177 of 279 (63.44%) changed or added relevant lines in 43 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 73.517%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/services/ib_engine_service.dart	3	5	60.0%
lib/ui/views/groups/add_assignment_view.dart	2	4	50.0%
lib/ui/views/groups/edit_group_view.dart	1	3	33.33%
lib/ui/views/groups/new_group_view.dart	1	3	33.33%
lib/ui/views/groups/update_assignment_view.dart	2	4	50.0%
lib/ui/views/profile/edit_profile_view.dart	1	3	33.33%
lib/ui/views/groups/my_groups_view.dart	2	5	40.0%
lib/ui/views/projects/edit_project_view.dart	0	3	0.0%
lib/ui/views/authentication/forgot_password_view.dart	1	5	20.0%
lib/ui/views/authentication/login_view.dart	1	5	20.0%

Totals
Change from base Build 1540966382:	0.01%
Covered Lines:	3853
Relevant Lines:	5241

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💛 - Coveralls

[manjotsidhu]

Thanks for contributing, I will review it soon.