improve readability: rename getType() -> getGType(), no functional change

git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3266 25d90789-57f7-4ee0-8453-03a3dfeeeb22
Implement new test for wrong use of routable line types:

1) warn when the style file lines uses types 0x02 - 0x09 without road class/speed if -check-styles is used
2) warn if a line is added multiple times, once with type between 0x01 and 0x3f and road class/speed,
once with type 0x02 - 0x09 and without road class/speed.

git-svn-id: http://svn.mkgmap.org.uk/mkgmap/trunk@3267 25d90789-57f7-4ee0-8453-03a3dfeeeb22