Extend bibliography.

Signed-off-by: Krzysztof Opasiak <ups100@tlen.pl>
Extend chapter about Icinga.

Add more schemas and emphasize things more clearly.

Signed-off-by: Krzysztof Opasiak <ups100@tlen.pl>
Update project chapter.

Signed-off-by: Krzysztof Opasiak <ups100@tlen.pl>
Update implementation chapter.

Signed-off-by: Krzysztof Opasiak <ups100@tlen.pl>