Added static CecilEqualityComparer.GetHashCode.
Fixed comparison methods in TypeDependency class.
Fixed --remove-external-types-usage for attributes.

Fixed --remove-external-types-usage not removing more than one attribute
from a member. Fix: Added equality comparison methods to
AttributeDependency.
AttributeDependency now stores the value of
customAttribute.AttributeType instead of a CustomAttribute instance.
Changed --enable-breaking-verification to --disable-breaking-verification

Changed --enable-breaking-verification to
--disable-breaking-verification and reversed the default value. Breaking
verification (by removing all private fields from the structs) is now
enabled by default.
CecilProcessor now allows deleting the currently processing object.
Added event removal to the RemovePrivateMembersProcessor.
Improved tracing in RemovePrivateMembersProcessor.
Added the --list-api command.