Fix wording in introduction

[christofferholmstedt]

The introduction says that Uppaal will be used to verify realtime requirements, but it seems it is only used for deadlock and livelock analysis, not any verification of timing.

[christofferholmstedt]

For me deadlock and livelock analyis is part of realtime requirements. No timing analysis was made that is correct.

Maybe a won't fix?

[christofferholmstedt]

Valid comment. Fixed.