Adding bug fixes and improvements (see description)

* Replace integer to bigint (OSM id reached the capacity of 32bit
integers) in Create DB code
* Replace tag class with map<string,string>
* Priority for given route types
* Max speed (for both directions: forward and backward)
* Added default priorities and max speed values to config
file(mapconfig_for_cars.xml)
Small bugfixes, improvements

-Fix assign_vertex_id parameters (missing 'public' schema)
-Add priority column directly to ways table, so future JOIN-s won't be
needed
Fix previously mentioned bug(assign_vertex_id)
Merge branch 'Plutoz01-own_edits' into mergetest
Updated Readme

Resolved Conflicts in:
	src/Export2DB.cpp
	src/Export2DB.h
	src/OSMDocumentParserCallback.cpp
	src/Way.h
	src/osm2pgrouting.cpp