Improve the format of error messages

Introduces a better (standardized) format for the error
messages(/exceptions).
It should be readable both by humans and machines.

Proposed format:
KacTalk Error: FunctionOrComponent->ErrorIdentifier(relevant,subjects) |
[Human readble comment about the error] in Class::Method()! #ErrorNumber

Example:
KacTalk Error: GetObject->UnavailableObject(foo)| [The object 'foo'
doesn't exist!] in kacTalk::Parse()! (ERR#3006)
Add a TODO document
Improve the examples in index.php
Fix the look up of classes and class names
Add a helper function to find objects in arrays
Handle objects that isn't derived from ktObject
Update copyright info
Improve the ktLib::IsInArray method

Adds an output value ($c, third argument) that will hold the key of the
found subject.
Improve the examples in index.php
Improve the method for retrieving class names