Use rspec tags to skip NIST related tests
Fix gaussian primitive codes
Require dependency
Readability
raondom_complex accepts range
Create bundle group for test coverage

[ci skip]
Make SimpleCov working

[ci skip]
Coverage tasks have the same prerequisites as the spec task has
Factor out configuration of spec tasks

[ci skip]
Fix a trivial bug

[ci skip]
Guardfile

all_on_start: true
failed_mode: :focus
[ci skip]
Travis: test the latest 2.0/2.1 release
Travis: Skip installing coverage gems
gem 'rb-gsl'

[ci skip]
Install GSL before running tests on Travis
Refactor tests for AO::Gaussian::PrimitiveProduct
Fix Gemfile to require gsl
Refactor tests for PrimitiveProduct#hermitian_coeff_decomposed
Fix wrong orders
Refactor test codes for PrimitiveProduct