Manage errors in analysis operations

[AML14]

Right now, errors are not managed inside analysis operations.

• Example 1: When "isDeadParameter" receives a parameter which doesn't exist, it returns "true" as output, i.e. as if the (nonexistent) parameter was dead.
• Example 2: When "isFalseOptional" receives a parameter which doesn't exist, an exception occurs, therefore the program exits.
• Example 3: When "isValidRequest" receives parameters which don't exist, an empty map is returned, as if the requestwas invalid. (Although this may be considered the right behaviour...).

These behaviours should be managed differently, for example, returning null in those cases or throwing an expected Exception.