Wiki details extraction and preparation

[mjoris]

I was considering to add some information on the Wiki about the extraction and preparation processes.
I compared https://github.com/DennisOSRM/Project-OSRM/wiki/Running-OSRM with my experiences and have some small questions in order to update the page:

• I suppose that the STXXL file space is only used during preparation and not during extraction. Is this right?
• As the command line output suggests the speed profile is only used during extraction. Is this right? Or are there speedprofile entries that are used during preparation? e.g. uTurnPenalty, TrafficLightPenalty If the answer is yes, are they also used by the routing engine?
• @DennisOSRM Do you agree with the memory peak mentioned in Extracting maps #314 ?

[DennisOSRM]

• STXXL is used during extraction only.
• The speedprofile is used during extraction and preparation. This is subject to change. See issue LUA script engine for speedprofiles #1
• Peak memory seems about right