add tests for controllers

94.87 coverage

From now on, any modification means a test modification first (TDD)
fix has_security_alerts name in SecurityAlert model

I was using the singular form "has_security_alert" in the
SecurityAlert model for refering to HasSecurityAlerts model.

Note that HasSecurityAlerts is plural. Thas was causing some confusion
in writing the code in the views and controllers and in writing the
fixtures for the tests.
add functional test for updading security alerts
review text in views
refactor 1/2: change class name HasChanged to HasNotChanged
refactor 2/2: Change has_changed filenames to has_not_changed
refactor 1/2 change has_security_alerts by has_not_security_alerts

to be more coherent with the rest of the checkers
refactor 2/2 change has_security_alerts by has_not_security_alerts
fix database after renaming has_security_alerts to
has_not_security_alerts
refactor change IsNative to IsNotNative 1/2
refactor change IsNative to IsNotNative 2/2

to be coherent with the other names
refactor: rename isGplCompatible to isNotGPL 1/2

What we want to check is that the gem is not gpl. Why? Because in the
case it is, you may have problems to distribute your software if yours
is not GPL compatible.
refactor rename is_gpl_compatible 2/2
review view and example data for gpl check
review rails apps view: only show a link if the check fails
add check descriptions and short names in the view

In order to make it more understandable