[test][is_valid] add one more test case: add a polygon with many holes
(important note here: many means more than the number of turns)
[algorithms][is_valid] fix bug in initialization of DFS data for
detecting cycles
Merge pull request #80 from mkaravel/feature/is_simple

Feature/is simple
[test][is_valid] add as test case the polygon used in the documentation
example for is_valid
[doc][examples] change the color used for drawing the geometry
[doc][examples][is_simple] add image
[doc][examples][is_valid] add image; slightly modify the example geometry
(one of the interior rings was having CW orientation instead of CCW)
[doc][images] add PNG images for is_valid and is_simple documentation
[doc][algorithms] add documentation for the comparable_distance free
function that takes a strategy
[algorithms][is_valid] remove obsolete comment
Merge pull request #82 from mkaravel/feature/distance

[doc][algorithms] add documentation for the comparable_distance free function that takes a strategy
Merge pull request #81 from mkaravel/feature/is_simple

Feature/is simple
[buffer] copy inserter to buffer_side
[buffer] move buffer_side to strategies
[buffer] use strategy buffer_side instead of generate_side
[buffer] use range instead of two points as output for buffer_side strategy
[buffer] restructure buffer_range such that tag is not necessary
and behaviour per geometry-type is done in the dispatch itself.
This also avoids generating side on perpendicular side for linestrings once
(the second one cannot easily be avoided in the current structure)
Merge branch 'develop' of github.com:boostorg/geometry into develop
[doc][examples][is_valid] remove inclusion of wkt.hpp
[doc][examples][is_simple] remove inclusion of wkt.hpp